.\" __COPYRIGHT__ .\" .\" Permission is hereby granted, free of charge, to any person obtaining .\" a copy of this software and associated documentation files (the .\" "Software"), to deal in the Software without restriction, including .\" without limitation the rights to use, copy, modify, merge, publish, .\" distribute, sublicense, and/or sell copies of the Software, and to .\" permit persons to whom the Software is furnished to do so, subject to .\" the following conditions: .\" .\" The above copyright notice and this permission notice shall be included .\" in all copies or substantial portions of the Software. .\" .\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY .\" KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE .\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND .\" NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE .\" LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION .\" OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION .\" WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. .\" .\" __FILE__ __REVISION__ __DATE__ __DEVELOPER__ .\" .\" ES - Example Start - indents and turns off line fill .de ES .RS .nf .. .\" EE - Example End - ends indent and turns line fill back on .de EE .fi .RE .. .TH SCONS 1 "December 2005" .SH NAME scons \- a software construction tool .SH SYNOPSIS .B scons [ .IR options ... ] [ .IR name = val ... ] [ .IR targets ... ] .SH DESCRIPTION The .B scons utility builds software (or other files) by determining which component pieces must be rebuilt and executing the necessary commands to rebuild them. By default, .B scons searches for a file named .IR SConstruct , .IR Sconstruct , or .I sconstruct (in that order) in the current directory and reads its configuration from the first file found. An alternate file name may be specified via the .B -f option. The .I SConstruct file can specify subsidiary configuration files using the .B SConscript() function. By convention, these subsidiary files are named .IR SConscript , although any name may be used. (Because of this naming convention, the term "SConscript files" is sometimes used to refer generically to all .B scons configuration files, regardless of actual file name.) The configuration files specify the target files to be built, and (optionally) the rules to build those targets. Reasonable default rules exist for building common software components (executable programs, object files, libraries), so that for most software projects, only the target and input files need be specified. .B scons reads and executes the SConscript files as Python scripts, so you may use normal Python scripting capabilities (such as flow control, data manipulation, and imported Python libraries) to handle complicated build situations. .BR scons , however, reads and executes all of the SConscript files .I before it begins building any targets. To make this obvious, .B scons prints the following messages about what it is doing: .ES $ scons foo.out scons: Reading SConscript files ... scons: done reading SConscript files. scons: Building targets ... cp foo.in foo.out scons: done building targets. $ .EE The status messages (everything except the line that reads "cp foo.in foo.out") may be suppressed using the .B -Q option. .B scons does not automatically propagate the external environment used to execute .B scons to the commands used to build target files. This is so that builds will be guaranteed repeatable regardless of the environment variables set at the time .B scons is invoked. This also means that if the compiler or other commands that you want to use to build your target files are not in standard system locations, .B scons will not find them unless you explicitly set the PATH to include those locations. Whenever you create an .B scons construction environment, you can propagate the value of PATH from your external environment as follows: .ES import os env = Environment(ENV = {'PATH' : os.environ['PATH']}) .EE Similarly, if the commands use external environment variables like $PATH, $HOME, $JAVA_HOME, $LANG, $SHELL, $TERM, etc., these variables can also be explicitly propagated: .ES import os env = Environment(ENV = {'PATH' : os.environ['PATH'], 'HOME' : os.environ['HOME']}) .EE Or you may explicitly propagate the invoking user's complete external environment: .ES import os env = Environment(ENV = os.environ['PATH']) .EE This comes at the expense of making your build dependent on the user's environment being set correctly, but it may be more convenient for many configurations. .B scons can scan known input files automatically for dependency information (for example, #include statements in C or C++ files) and will rebuild dependent files appropriately whenever any "included" input file changes. .B scons supports the ability to define new scanners for unknown input file types. .B scons knows how to fetch files automatically from SCCS or RCS subdirectories using SCCS, RCS or BitKeeper. .B scons is normally executed in a top-level directory containing a .I SConstruct file, optionally specifying as command-line arguments the target file or files to be built. By default, the command .ES scons .EE will build all target files in or below the current directory. Explicit default targets (to be built when no targets are specified on the command line) may be defined the SConscript file(s) using the .B Default() function, described below. Even when .B Default() targets are specified in the SConscript file(s), all target files in or below the current directory may be built by explicitly specifying the current directory (.) as a command-line target: .ES scons . .EE Building all target files, including any files outside of the current directory, may be specified by supplying a command-line target of the root directory (on POSIX systems): .ES scons / .EE or the path name(s) of the volume(s) in which all the targets should be built (on Windows systems): .ES scons C:\\ D:\\ .EE To build only specific targets, supply them as command-line arguments: .ES scons foo bar .EE in which case only the specified targets will be built (along with any derived files on which they depend). Specifying "cleanup" targets in SConscript files is not necessary. The .B -c flag removes all files necessary to build the specified target: .ES scons -c . .EE to remove all target files, or: .ES scons -c build export .EE to remove target files under build and export. Additional files or directories to remove can be specified using the .BR Clean() function. Conversely, targets that would normally be removed by the .B -c invocation can be prevented from being removed by using the .BR NoClean () function. A subset of a hierarchical tree may be built by remaining at the top-level directory (where the .I SConstruct file lives) and specifying the subdirectory as the target to be built: .ES scons src/subdir .EE or by changing directory and invoking scons with the .B -u option, which traverses up the directory hierarchy until it finds the .I SConstruct file, and then builds targets relatively to the current subdirectory: .ES cd src/subdir scons -u . .EE .B scons supports building multiple targets in parallel via a .B -j option that takes, as its argument, the number of simultaneous tasks that may be spawned: .ES scons -j 4 .EE builds four targets in parallel, for example. .B scons can maintain a cache of target (derived) files that can be shared between multiple builds. When caching is enabled in a SConscript file, any target files built by .B scons will be copied to the cache. If an up-to-date target file is found in the cache, it will be retrieved from the cache instead of being rebuilt locally. Caching behavior may be disabled and controlled in other ways by the .BR --cache-force , .BR --cache-disable , and .B --cache-show command-line options. The .B --random option is useful to prevent multiple builds from trying to update the cache simultaneously. Values of variables to be passed to the SConscript file(s) may be specified on the command line: .ES scons debug=1 . .EE These variables are available in SConscript files through the ARGUMENTS dictionary, and can be used in the SConscript file(s) to modify the build in any way: .ES if ARGUMENTS.get('debug', 0): env = Environment(CCFLAGS = '-g') else: env = Environment() .EE The command-line variable arguments are also available in the ARGLIST list, indexed by their order on the command line. This allows you to process them in order rather than by name, if necessary. ARGLIST[0] returns a tuple containing (argname, argvalue). A Python exception is thrown if you try to access a list member that does not exist. .B scons requires Python version 1.5.2 or later. There should be no other dependencies or requirements to run .B scons. .\" The following paragraph reflects the default tool search orders .\" currently in SCons/Tool/__init__.py. If any of those search orders .\" change, this documentation should change, too. By default, .B scons knows how to search for available programming tools on various systems. On Windows systems, .B scons searches in order for the Microsoft Visual C++ tools, the MinGW tool chain, the Intel compiler tools, and the PharLap ETS compiler. On OS/2 systems, .B scons searches in order for the OS/2 compiler, the GCC tool chain, and the Microsoft Visual C++ tools, On SGI IRIX, IBM AIX, Hewlett Packard HP-UX, and Sun Solaris systems, .B scons searches for the native compiler tools (MIPSpro, Visual Age, aCC, and Forte tools respectively) and the GCC tool chain. On all other platforms, including POSIX (Linux and UNIX) platforms, .B scons searches in order for the GCC tool chain, the Microsoft Visual C++ tools, and the Intel compiler tools. You may, of course, override these default values by appropriate configuration of Environment construction variables. .SH OPTIONS In general, .B scons supports the same command-line options as GNU .BR make , and many of those supported by .BR cons . .TP -b Ignored for compatibility with non-GNU versions of .BR make. .TP -c, --clean, --remove Clean up by removing all target files for which a construction command is specified. Also remove any files or directories associated to the construction command using the .BR Clean () function. Will not remove any targets specified by the .BR NoClean () function. .TP .RI --cache-debug= file Print debug information about the .BR CacheDir () derived-file caching to the specified .IR file . If .I file is .B \- (a hyphen), the debug information are printed to the standard output. The printed messages describe what signature file names are being looked for in, retrieved from, or written to the .BR CacheDir () directory tree. .TP --cache-disable, --no-cache Disable the derived-file caching specified by .BR CacheDir (). .B scons will neither retrieve files from the cache nor copy files to the cache. .TP --cache-force, --cache-populate When using .BR CacheDir (), populate a cache by copying any already-existing, up-to-date derived files to the cache, in addition to files built by this invocation. This is useful to populate a new cache with all the current derived files, or to add to the cache any derived files recently built with caching disabled via the .B --cache-disable option. .TP --cache-show When using .BR CacheDir () and retrieving a derived file from the cache, show the command that would have been executed to build the file, instead of the usual report, "Retrieved `file' from cache." This will produce consistent output for build logs, regardless of whether a target file was rebuilt or retrieved from the cache. .TP .RI --config= mode This specifies how the .B Configure call should use or generate the results of configuration tests. The option should be specified from among the following choices: .TP --config=auto scons will use its normal dependency mechanisms to decide if a test must be rebuilt or not. This saves time by not running the same configuration tests every time you invoke scons, but will overlook changes in system header files or external commands (such as compilers) if you don't specify those dependecies explicitly. This is the default behavior. .TP --config=force If this option is specified, all configuration tests will be re-run regardless of whether the cached results are out of date. This can be used to explicitly force the configuration tests to be updated in response to an otherwise unconfigured change in a system header file or compiler. .TP --config=cache If this option is specified, no configuration tests will be rerun and all results will be taken from cache. Note that scons will still consider it an error if --config=cache is specified and a necessary test does not yet have any results in the cache. .TP .RI "-C" " directory" ", --directory=" directory Change to the specified .I directory before searching for the .IR SConstruct , .IR Sconstruct , or .I sconstruct file, or doing anything else. Multiple .B -C options are interpreted relative to the previous one, and the right-most .B -C option wins. (This option is nearly equivalent to .BR "-f directory/SConstruct" , except that it will search for .IR SConstruct , .IR Sconstruct , or .I sconstruct in the specified directory.) .\" .TP .\" -d .\" Display dependencies while building target files. Useful for .\" figuring out why a specific file is being rebuilt, as well as .\" general debugging of the build process. .TP -D Works exactly the same way as the .B -u option except for the way default targets are handled. When this option is used and no targets are specified on the command line, all default targets are built, whether or not they are below the current directory. .TP .RI --debug= type Debug the build process. .I type specifies what type of debugging: .TP --debug=count Print how many objects are created of the various classes used internally by SCons before and after reading the SConscript files and before and after building targets. This only works when run under Python 2.1 or later. .TP --debug=dtree Print the dependency tree after each top-level target is built. This prints out only derived files. .TP --debug=explain Print an explanation of precisely why .B scons is deciding to (re-)build any targets. (Note: this does not print anything for targets that are .I not rebuilt.) .TP --debug=findlibs Instruct the scanner that searches for libraries to print a message about each potential library name it is searching for, and about the actual libraries it finds. .TP --debug=includes Print the include tree after each top-level target is built. This is generally used to find out what files are included by the sources of a given derived file: .ES $ scons --debug=includes foo.o .EE .TP --debug=memoizer Prints a summary of hits and misses in the Memoizer, the internal SCons subsystem for caching various values in memory instead of recomputing them each time they're needed. .TP --debug=memory Prints how much memory SCons uses before and after reading the SConscript files and before and after building targets. .TP --debug=nomemoizer Disables use of the Memoizer, the internal SCons subsystem for caching various values in memory instead of recomputing them each time they're needed. This provides more accurate counts of the underlying function calls in the Python profiler output when using the .RI --profile= option. (When the Memoizer is used, the profiler counts all memoized functions as being executed by the Memoizer's wrapper calls.) .TP --debug=objects Prints a list of the various objects of the various classes used internally by SCons. This only works when run under Python 2.1 or later. .TP --debug=pdb Re-run SCons under the control of the .RI pdb Python debugger. .TP --debug=presub Print the raw command line used to build each target before the construction environment variables are substituted. Also shows which targets are being built by this command. Output looks something like this: .ES $ scons --debug=presub Building myprog.o with action(s): $SHCC $SHCCFLAGS $CPPFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES ... .EE .TP --debug=stacktrace Prints an internal Python stack trace when encountering an otherwise unexplained error. .TP --debug=stree Print the dependency tree along with status information. This is the same as the debug=tree option, but additional status information is provided for each node in the tree. .TP --debug=time Prints various time profiling information: the time spent executing each build command, the total build time, the total time spent executing build commands, the total time spent executing SConstruct and SConscript files, and the total time spent executing SCons itself. .TP --debug=tree Print the dependency tree after each top-level target is built. This prints out the complete dependency tree including implicit dependencies and ignored dependencies. .TP .RI --diskcheck= types Enable specific checks for whether or not there is a file on disk where the SCons configuration expects a directory (or vice versa), and whether or not RCS or SCCS sources exist when searching for source and include files. The .I types argument can be set to: .BR all , to enable all checks explicitly (the default behavior); .BR none , to disable all such checks; .BR match , to check that files and directories on disk match SCons' expected configuration; .BR rcs , to check for the existence of an RCS source for any missing source or include files; .BR sccs , to check for the existence of an SCCS source for any missing source or include files. Multiple checks can be specified separated by commas; for example, .B --diskcheck=sccs,rcs would still check for SCCS and RCS sources, but disable the check for on-disk matches of files and directories. Disabling some or all of these checks can provide a performance boost for large configurations, or when the configuration will check for files and/or directories across networked or shared file systems, at the slight increased risk of an incorrect build or of not handling errors gracefully (if include files really should be found in SCCS or RCS, for example, or if a file really does exist where the SCons configuration expects a directory). .\" .TP .\" -e, --environment-overrides .\" Variables from the execution environment override construction .\" variables from the SConscript files. .TP .RI -f " file" ", --file=" file ", --makefile=" file ", --sconstruct=" file Use .I file as the initial SConscript file. .TP -h, --help Print a local help message for this build, if one is defined in the SConscript file(s), plus a line that describes the .B -H option for command-line option help. If no local help message is defined, prints the standard help message about command-line options. Exits after displaying the appropriate message. .TP -H, --help-options Print the standard help message about command-line options and exit. .TP -i, --ignore-errors Ignore all errors from commands executed to rebuild files. .TP .RI -I " directory" ", --include-dir=" directory Specifies a .I directory to search for imported Python modules. If several .B -I options are used, the directories are searched in the order specified. .TP --implicit-cache Cache implicit dependencies. This can cause .B scons to miss changes in the implicit dependencies in cases where a new implicit dependency is added earlier in the implicit dependency search path (e.g. CPPPATH) than a current implicit dependency with the same name. .TP --implicit-deps-changed Force SCons to ignore the cached implicit dependencies. This causes the implicit dependencies to be rescanned and recached. This implies .BR --implicit-cache . .TP --implicit-deps-unchanged Force SCons to ignore changes in the implicit dependencies. This causes cached implicit dependencies to always be used. This implies .BR --implicit-cache . .TP .RI -j " N" ", --jobs=" N Specifies the number of jobs (commands) to run simultaneously. If there is more than one .B -j option, the last one is effective. .\" ??? If the .\" .B -j .\" option .\" is specified without an argument, .\" .B scons .\" will not limit the number of .\" simultaneous jobs. .TP -k, --keep-going Continue as much as possible after an error. The target that failed and those that depend on it will not be remade, but other targets specified on the command line will still be processed. .\" .TP .\" .RI -l " N" ", --load-average=" N ", --max-load=" N .\" No new jobs (commands) will be started if .\" there are other jobs running and the system load .\" average is at least .\" .I N .\" (a floating-point number). .TP .RI --duplicate= ORDER There are three ways to duplicate files in a build tree: hard links, soft (symbolic) links and copies. The default behaviour of SCons is to prefer hard links to soft links to copies. You can specify different behaviours with this option. .IR ORDER must be one of .IR hard-soft-copy (the default), .IR soft-hard-copy , .IR hard-copy , .IR soft-copy or .IR copy . SCons will attempt to duplicate files using the mechanisms in the specified order. .\" .\" .TP .\" --list-derived .\" List derived files (targets, dependencies) that would be built, .\" but do not build them. .\" [XXX This can probably go away with the right .\" combination of other options. Revisit this issue.] .\" .\" .TP .\" --list-actions .\" List derived files that would be built, with the actions .\" (commands) that build them. Does not build the files. .\" [XXX This can probably go away with the right .\" combination of other options. Revisit this issue.] .\" .\" .TP .\" --list-where .\" List derived files that would be built, plus where the file is .\" defined (file name and line number). Does not build the files. .\" [XXX This can probably go away with the right .\" combination of other options. Revisit this issue.] .TP -m Ignored for compatibility with non-GNU versions of .BR make . .TP .RI --max-drift= SECONDS Set the maximum expected drift in the modification time of files to .IR SECONDS . This value determines how long a file must be unmodified before its cached content signature will be used instead of calculating a new content signature (MD5 checksum) of the file's contents. The default value is 2 days, which means a file must have a modification time of at least two days ago in order to have its cached content signature used. A negative value means to never cache the content signature and to ignore the cached value if there already is one. A value of 0 means to always use the cached signature, no matter how old the file is. .TP -n, --just-print, --dry-run, --recon No execute. Print the commands that would be executed to build any out-of-date target files, but do not execute the commands. .\" .TP .\" .RI -o " file" ", --old-file=" file ", --assume-old=" file .\" Do not rebuild .\" .IR file , .\" and do .\" not rebuild anything due to changes in the contents of .\" .IR file . .\" .TP .\" .RI --override " file" .\" Read values to override specific build environment variables .\" from the specified .\" .IR file . .\" .TP .\" -p .\" Print the data base (construction environments, .\" Builder and Scanner objects) that are defined .\" after reading the SConscript files. .\" After printing, a normal build is performed .\" as usual, as specified by other command-line options. .\" This also prints version information .\" printed by the .\" .B -v .\" option. .\" .\" To print the database without performing a build do: .\" .\" .ES .\" scons -p -q .\" .EE .TP .RI --profile= file Run SCons under the Python profiler and save the results in the specified .IR file . The results may be analyzed using the Python pstats module. .TP -q, --question Do not run any commands, or print anything. Just return an exit status that is zero if the specified targets are already up to date, non-zero otherwise. .TP -Q Quiets SCons status messages about reading SConscript files, building targets and entering directories. Commands that are executed to rebuild target files are still printed. .\" .TP .\" -r, -R, --no-builtin-rules, --no-builtin-variables .\" Clear the default construction variables. Construction .\" environments that are created will be completely empty. .TP --random Build dependencies in a random order. This is useful when building multiple trees simultaneously with caching enabled, to prevent multiple builds from simultaneously trying to build or retrieve the same target files. .TP -s, --silent, --quiet Silent. Do not print commands that are executed to rebuild target files. Also suppresses SCons status messages. .TP -S, --no-keep-going, --stop Ignored for compatibility with GNU .BR make . .TP -t, --touch Ignored for compatibility with GNU .BR make . (Touching a file to make it appear up-to-date is unnecessary when using .BR scons .) .TP .RI --taskmastertrace= file Prints trace information to the specified .I file about how the internal Taskmaster object evaluates and controls the order in which Nodes are built. A file name of .B - may be used to specify the standard output. .TP -u, --up, --search-up Walks up the directory structure until an .I SConstruct , .I Sconstruct or .I sconstruct file is found, and uses that as the top of the directory tree. If no targets are specified on the command line, only targets at or below the current directory will be built. .TP -U Works exactly the same way as the .B -u option except for the way default targets are handled. When this option is used and no targets are specified on the command line, all default targets that are defined in the SConscript(s) in the current directory are built, regardless of what directory the resultant targets end up in. .TP -v, --version Print the .B scons version, copyright information, list of authors, and any other relevant information. Then exit. .TP -w, --print-directory Print a message containing the working directory before and after other processing. .TP .RI --warn= type ", --warn=no-" type Enable or disable warnings. .I type specifies the type of warnings to be enabled or disabled: .TP --warn=all, --warn=no-all Enables or disables all warnings. .TP --warn=dependency, --warn=no-dependency Enables or disables warnings about dependencies. These warnings are disabled by default. .TP --warn=deprecated, --warn=no-deprecated Enables or disables warnings about use of deprecated features. These warnings are enabled by default. .TP --warn=missing-sconscript, --warn=no-missing-sconscript Enables or disables warnings about missing SConscript files. These warnings are enabled by default. .TP --no-print-directory Turn off -w, even if it was turned on implicitly. .\" .TP .\" .RI --write-filenames= file .\" Write all filenames considered into .\" .IR file . .\" .\" .TP .\" .RI -W " file" ", --what-if=" file ", --new-file=" file ", --assume-new=" file .\" Pretend that the target .\" .I file .\" has been .\" modified. When used with the .\" .B -n .\" option, this .\" show you what would be rebuilt if you were to modify that file. .\" Without .\" .B -n .\" ... what? XXX .\" .\" .TP .\" --warn-undefined-variables .\" Warn when an undefined variable is referenced. .TP .RI -Y " repository" ", --repository=" repository Search the specified repository for any input and target files not found in the local directory hierarchy. Multiple .B -Y options may specified, in which case the repositories are searched in the order specified. .SH CONFIGURATION FILE REFERENCE .\" .SS Python Basics .\" XXX Adding this in the future would be a help. .SS Construction Environments A construction environment is the basic means by which the SConscript files communicate build information to .BR scons . A new construction environment is created using the .B Environment function: .ES env = Environment() .EE By default, a new construction environment is initialized with a set of builder methods and construction variables that are appropriate for the current platform. An optional platform keyword argument may be used to specify that an environment should be initialized for a different platform: .ES env = Environment(platform = 'cygwin') env = Environment(platform = 'os2') env = Environment(platform = 'posix') env = Environment(platform = 'win32') .EE Specifying a platform initializes the appropriate construction variables in the environment to use and generate file names with prefixes and suffixes appropriate for the platform. Note that the .B win32 platform adds the .B SYSTEMDRIVE and .B SYSTEMROOT variables from the user's external environment to the construction environment's .B ENV dictionary. This is so that any executed commands that use sockets to connect with other systems (such as fetching source files from external CVS repository specifications like .BR :pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons ) will work on Windows systems. The platform argument may be function or callable object, in which case the Environment() method will call the specified argument to update the new construction environment: .ES def my_platform(env): env['VAR'] = 'xyzzy' env = Environment(platform = my_platform) .EE Additionally, a specific set of tools with which to initialize the environment may specified as an optional keyword argument: .ES env = Environment(tools = ['msvc', 'lex']) .EE Non-built-in tools may be specified using the toolpath argument: .ES env = Environment(tools = ['default', 'foo'], toolpath = ['tools']) .EE This looks for a tool specification in tools/foo.py (as well as using the ordinary default tools for the platform). foo.py should have two functions: generate(env, **kw) and exists(env). The .B generate() function modifies the passed-in environment to set up variables so that the tool can be executed; it may use any keyword arguments that the user supplies (see below) to vary its initialization. The .B exists() function should return a true value if the tool is available. Tools in the toolpath are used before any of the built-in ones. For example, adding gcc.py to the toolpath would override the built-in gcc tool. Also note that the toolpath is stored in the environment for use by later calls to .BR Clone () and .BR Tool () methods: .ES base = Environment(toolpath=['custom_path']) derived = base.Clone(tools=['custom_tool']) derived.CustomBuilder() .EE The elements of the tools list may also be functions or callable objects, in which case the Environment() method will call the specified elements to update the new construction environment: .ES def my_tool(env): env['XYZZY'] = 'xyzzy' env = Environment(tools = [my_tool]) .EE The individual elements of the tools list may also themselves be two-element lists of the form .RI ( toolname ", " kw_dict ). SCons searches for the .I toolname specification file as described above, and passes .IR kw_dict , which must be a dictionary, as keyword arguments to the tool's .B generate function. The .B generate function can use the arguments to modify the tool's behavior by setting up the environment in different ways or otherwise changing its initialization. .ES # in tools/my_tool.py: def generate(env, **kw): # Sets MY_TOOL to the value of keyword argument 'arg1' or 1. env['MY_TOOL'] = kw.get('arg1', '1') def exists(env): return 1 # in SConstruct: env = Environment(tools = ['default', ('my_tool', {'arg1': 'abc'})], toolpath=['tools']) .EE The tool definition (i.e. my_tool()) can use the PLATFORM variable from the environment it receives to customize the tool for different platforms. If no tool list is specified, then SCons will auto-detect the installed tools using the PATH variable in the ENV construction variable and the platform name when the Environment is constructed. Changing the PATH variable after the Environment is constructed will not cause the tools to be redetected. SCons supports the following tool specifications out of the box: .ES 386asm aixc++ aixcc aixf77 aixlink ar as bcc32 c++ cc cvf dmd dvipdf dvips f77 f90 f95 fortran g++ g77 gas gcc gnulink gs hpc++ hpcc hplink icc icl ifl ifort ilink ilink32 intelc jar javac javah latex lex link linkloc m4 masm midl mingw mslib mslink msvc msvs mwcc mwld nasm pdflatex pdftex qt rmic rpcgen sgiar sgic++ sgicc sgilink sunar sunc++ suncc sunlink swig tar tex tlib yacc zip .EE Additionally, there is a "tool" named .B default which configures the environment with a default set of tools for the current platform. On posix and cygwin platforms the GNU tools (e.g. gcc) are preferred by SCons, on Windows the Microsoft tools (e.g. msvc) followed by MinGW are preferred by SCons, and in OS/2 the IBM tools (e.g. icc) are preferred by SCons. .SS Builder Methods Build rules are specified by calling a construction environment's builder methods. The arguments to the builder methods are .B target (a list of target files) and .B source (a list of source files). Because long lists of file names can lead to a lot of quoting, .B scons supplies a .B Split() global function and a same-named environment method that split a single string into a list, separated on strings of white-space characters. (These are similar to the string.split() method from the standard Python library, but work even if the input isn't a string.) Like all Python arguments, the target and source arguments to a builder method can be specified either with or without the "target" and "source" keywords. When the keywords are omitted, the target is first, followed by the source. The following are equivalent examples of calling the Program builder method: .ES env.Program('bar', ['bar.c', 'foo.c']) env.Program('bar', Split('bar.c foo.c')) env.Program('bar', env.Split('bar.c foo.c')) env.Program(source = ['bar.c', 'foo.c'], target = 'bar') env.Program(target = 'bar', Split('bar.c foo.c')) env.Program(target = 'bar', env.Split('bar.c foo.c')) env.Program('bar', source = string.split('bar.c foo.c')) .EE When the target shares the same base name as the source and only the suffix varies, and if the builder method has a suffix defined for the target file type, then the target argument may be omitted completely, and .B scons will deduce the target file name from the source file name. The following examples all build the executable program .B bar (on POSIX systems) or .B bar.exe (on Windows systems) from the bar.c source file: .ES env.Program(target = 'bar', source = 'bar.c') env.Program('bar', source = 'bar.c') env.Program(source = 'bar.c') env.Program('bar.c') .EE It is possible to override or add construction variables when calling a builder method by passing additional keyword arguments. These overridden or added variables will only be in effect when building the target, so they will not affect other parts of the build. For example, if you want to add additional libraries for just one program: .ES env.Program('hello', 'hello.c', LIBS=['gl', 'glut']) .EE or generate a shared library with a non-standard suffix: .ES env.SharedLibrary('word', 'word.cpp', SHLIBSUFFIX='.ocx', LIBSUFFIXES=['.ocx']) .EE (Note that both the $SHLIBSUFFIX and $LIBSUFFIXES variables must be set if you want SCons to search automatically for dependencies on the non-standard library names; see the descriptions of these variables, below, for more information.) Although the builder methods defined by .B scons are, in fact, methods of a construction environment object, they may also be called without an explicit environment: .ES Program('hello', 'hello.c') SharedLibrary('word', 'word.cpp') .EE In this case, the methods are called internally using a default construction environment that consists of the tools and values that .B scons has determined are appropriate for the local system. Builder methods that can be called without an explicit environment may be called from custom Python modules that you import into an SConscript file by adding the following to the Python module: .ES from SCons.Script import * .EE All builder methods return a list of Nodes that represent the target or targets that will be built. A .I Node is an internal SCons object which represents build targets or sources. The returned Node(s) can be passed to other builder methods as source(s) or passed to any SCons function or method where a filename would normally be accepted. For example, if it were necessary to add a specific .B -D flag when compiling one specific object file: .ES bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR') env.Program(source = ['foo.c', bar_obj_list, 'main.c']) .EE Using a Node in this way makes for a more portable build by avoiding having to specify a platform-specific object suffix when calling the Program() builder method. Note that Builder calls will automatically "flatten" the source and target file lists, so it's all right to have the bar_obj list return by the StaticObject() call in the middle of the source file list. If you need to manipulate a list of lists returned by Builders directly using Python, you can either build the list by hand: .ES foo = Object('foo.c') bar = Object('bar.c') objects = ['begin.o'] + foo + ['middle.o'] + bar + ['end.o'] for object in objects: print str(object) .EE Or you can use the .BR Flatten () supplied by scons to create a list containing just the Nodes, which may be more convenient: .ES foo = Object('foo.c') bar = Object('bar.c') objects = Flatten(['begin.o', foo, 'middle.o', bar, 'end.o']) for object in objects: print str(object) .EE The path name for a Node's file may be used by passing the Node to the Python-builtin .B str() function: .ES bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR') print "The path to bar_obj is:", str(bar_obj_list[0]) .EE Note again that because the Builder call returns a list, we have to access the first element in the list .B (bar_obj_list[0]) to get at the Node that actually represents the object file. Builder calls support a .B chdir keyword argument that specifies that the Builder's action(s) should be executed after changing directory. If the .B chdir argument is a string or a directory Node, scons will change to the specified directory. If the .B chdir is not a string or Node and is non-zero, then scons will change to the target file's directory. .ES # scons will change to the "sub" subdirectory # before executing the "cp" command. env.Command('sub/dir/foo.out', 'sub/dir/foo.in', "cp dir/foo.in dir/foo.out", chdir='sub') # Because chdir is not a string, scons will change to the # target's directory ("sub/dir") before executing the # "cp" command. env.Command('sub/dir/foo.out', 'sub/dir/foo.in', "cp foo.in foo.out", chdir=1) .EE Note that scons will .I not automatically modify its expansion of construction variables like .B $TARGET and .B $SOURCE when using the chdir keyword argument--that is, the expanded file names will still be relative to the top-level SConstruct directory, and consequently incorrect relative to the chdir directory. If you use the chdir keyword argument, you will typically need to supply a different command line using expansions like .B ${TARGET.file} and .B ${SOURCE.file} to use just the filename portion of the targets and source. .B scons provides the following builder methods: '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" '\" BEGIN GENERATED BUILDER DESCRIPTIONS '\" '\" The descriptions below of the various SCons Builders are generated '\" from the .xml files that live next to the various Python modules in '\" the build enginer library. If you're reading this [gnt]roff file '\" with an eye towards patching this man page, you can still submit '\" a diff against this text, but it will have to be translated to a '\" diff against the underlying .xml file before the patch is actually '\" accepted. If you do that yourself, it will make it easier to '\" integrate the patch. '\" '\" BEGIN GENERATED BUILDER DESCRIPTIONS '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .so builders.man '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" '\" END GENERATED BUILDER DESCRIPTIONS '\" '\" The descriptions above of the various SCons Builders are generated '\" from the .xml files that live next to the various Python modules in '\" the build enginer library. If you're reading this [gnt]roff file '\" with an eye towards patching this man page, you can still submit '\" a diff against this text, but it will have to be translated to a '\" diff against the underlying .xml file before the patch is actually '\" accepted. If you do that yourself, it will make it easier to '\" integrate the patch. '\" '\" END GENERATED BUILDER DESCRIPTIONS '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" All targets of builder methods automatically depend on their sources. An explicit dependency can be specified using the .B Depends method of a construction environment (see below). In addition, .B scons automatically scans source files for various programming languages, so the dependencies do not need to be specified explicitly. By default, SCons can C source files, C++ source files, Fortran source files with .B .F (POSIX systems only), .B .fpp, or .B .FPP file extensions, and assembly language files with .B .S (POSIX systems only), .B .spp, or .B .SPP files extensions for C preprocessor dependencies. SCons also has default support for scanning D source files, You can also write your own Scanners to add support for additional source file types. These can be added to the default Scanner object used by the .BR Object () .BR StaticObject () and .BR SharedObject () Builders by adding them to the .B SourceFileScanner object as follows: See the section "Scanner Objects," below, for a more information about defining your own Scanner objects. .SS Methods and Functions to Do Things In addition to Builder methods, .B scons provides a number of other construction environment methods and global functions to manipulate the build configuration. Usually, a construction environment method and global function with the same name both exist so that you don't have to remember whether to a specific bit of functionality must be called with or without a construction environment. In the following list, if you call something as a global function it looks like: .ES .RI Function( arguments ) .EE and if you call something through a construction environment it looks like: .ES .RI env.Function( arguments ) .EE If you can call the functionality in both ways, then both forms are listed. Global functions may be called from custom Python modules that you import into an SConscript file by adding the following to the Python module: .ES from SCons.Script import * .EE Except where otherwise noted, the same-named construction environment method and global function provide the exact same functionality. The only difference is that, where appropriate, calling the functionality through a construction environment will substitute construction variables into any supplied strings. For example: .ES env = Environment(FOO = 'foo') Default('$FOO') env.Default('$FOO') .EE the first call to the global .B Default() function will actually add a target named .B $FOO to the list of default targets, while the second call to the .B env.Default() construction environment method will expand the value and add a target named .B foo to the list of default targets. For more on construction variable expansion, see the next section on construction variables. Construction environment methods and global functions supported by .B scons include: '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Action( action ", [" strfunction ", " varlist ]) .TP .RI env.Action( action ", [" strfunction ", " varlist ]) Creates an Action object for the specified .IR action . See the section "Action Objects," below, for a complete explanation of the arguments and behavior. Note that the .BR env.Action () form of the invocation will expand construction variables in any arguments strings, including the .I action argument, at the time it is called using the construction variables in the .B env construction environment through which .BR env.Action () was called. The .BR Action () form delays all variable expansion until the Action object is actually used. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI AddPostAction( target ", " action ) .TP .RI env.AddPostAction( target ", " action ) Arranges for the specified .I action to be performed after the specified .I target has been built. The specified action(s) may be an Action object, or anything that can be converted into an Action object (see below). '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI AddPreAction( target ", " action ) .TP .RI env.AddPreAction( target ", " action ) Arranges for the specified .I action to be performed before the specified .I target is built. The specified action(s) may be an Action object, or anything that can be converted into an Action object (see below). '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Alias( alias ", [" targets ", [" action ]]) .TP .RI env.Alias( alias ", [" targets ", [" action ]]) Creates one or more phony targets that expand to one or more other targets. An optional .I action (command) or list of actions can be specified that will be executed whenever the any of the alias targets are out-of-date. Returns the Node object representing the alias, which exists outside of any file system. This Node object, or the alias name, may be used as a dependency of any other target, including another alias. .B Alias can be called multiple times for the same alias to add additional targets to the alias, or additional actions to the list for this alias. .ES Alias('install') Alias('install', '/usr/bin') Alias(['install', 'install-lib'], '/usr/local/lib') env.Alias('install', ['/usr/local/bin', '/usr/local/lib']) env.Alias('install', ['/usr/local/man']) env.Alias('update', ['file1', 'file2'], "update_database $SOURCES") .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI AlwaysBuild( target ", ...)" .TP .RI env.AlwaysBuild( target ", ...)" Marks each given .I target so that it is always assumed to be out of date, and will always be rebuilt if needed. Note, however, that .BR AlwaysBuild () does not add its target(s) to the default target list, so the targets will only be built if they are specified on the command line, or are a dependent of a target specified on the command line--but they will .I always be built if so specified. Multiple targets can be passed in to a single call to .BR AlwaysBuild (). '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Append( key = val ", [...])" Appends the specified keyword arguments to the end of construction variables in the environment. If the Environment does not have the specified construction variable, it is simply added to the environment. If the values of the construction variable and the keyword argument are the same type, then the two values will be simply added together. Otherwise, the construction variable and the value of the keyword argument are both coerced to lists, and the lists are added together. (See also the Prepend method, below.) .ES env.Append(CCFLAGS = ' -g', FOO = ['foo.yyy']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.AppendENVPath( name ", " newpath ", [" envname ", " sep ]) This appends new path elements to the given path in the specified external environment .RB ( ENV by default). This will only add any particular path once (leaving the last one it encounters and ignoring the rest, to preserve path order), and to help assure this, will normalize all paths (using .B os.path.normpath and .BR os.path.normcase ). This can also handle the case where the given old path variable is a list instead of a string, in which case a list will be returned instead of a string. Example: .ES print 'before:',env['ENV']['INCLUDE'] include_path = '/foo/bar:/foo' env.AppendENVPath('INCLUDE', include_path) print 'after:',env['ENV']['INCLUDE'] yields: before: /foo:/biz after: /biz:/foo/bar:/foo .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.AppendUnique( key = val ", [...])" Appends the specified keyword arguments to the end of construction variables in the environment. If the Environment does not have the specified construction variable, it is simply added to the environment. If the construction variable being appended to is a list, then any value(s) that already exist in the construction variable will .I not be added again to the list. .ES env.AppendUnique(CCFLAGS = '-g', FOO = ['foo.yyy']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP env.BitKeeper() A factory function that returns a Builder object to be used to fetch source files using BitKeeper. The returned Builder is intended to be passed to the .B SourceCode function. .ES env.SourceCode('.', env.BitKeeper()) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI BuildDir( build_dir ", " src_dir ", [" duplicate ]) .TP .RI env.BuildDir( build_dir ", " src_dir ", [" duplicate ]) This specifies a build directory .I build_dir in which to build all derived files that would normally be built under .IR src_dir . Multiple build directories can be set up for multiple build variants, for example. .I src_dir must be underneath the SConstruct file's directory, and .I build_dir may not be underneath the .I src_dir . The default behavior is for .B scons to duplicate all of the files in the tree underneath .I src_dir into .IR build_dir , and then build the derived files within the copied tree. (The duplication is performed by linking or copying, depending on the platform; see also the .IR --duplicate option.) This guarantees correct builds regardless of whether intermediate source files are generated during the build, where preprocessors or other scanners search for included files, or whether individual compilers or other invoked tools are hard-coded to put derived files in the same directory as source files. This behavior of making a complete copy of the source tree may be disabled by setting .I duplicate to 0. This will cause .B scons to invoke Builders using the path names of source files in .I src_dir and the path names of derived files within .IR build_dir . This is always more efficient than .IR duplicate =1, and is usually safe for most builds. Specifying .IR duplicate =0, however, may cause build problems if source files are generated during the build, if any invoked tools are hard-coded to put derived files in the same directory as the source files. Note that specifying a .B BuildDir works most naturally with a subsidiary SConscript file in the source directory. However, you would then call the subsidiary SConscript file not in the source directory, but in the .I build_dir , as if .B scons had made a virtual copy of the source tree regardless of the value of .IR duplicate . This is how you tell .B scons which variant of a source tree to build. For example: .ES BuildDir('build-variant1', 'src') SConscript('build-variant1/SConscript') BuildDir('build-variant2', 'src') SConscript('build-variant2/SConscript') .EE .IP See also the .BR SConscript () function, described below, for another way to specify a build directory in conjunction with calling a subsidiary SConscript file.) '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Builder( action ", [" arguments ]) .TP .RI env.Builder( action ", [" arguments ]) Creates a Builder object for the specified .IR action . See the section "Builder Objects," below, for a complete explanation of the arguments and behavior. Note that the .BR env.Builder () form of the invocation will expand construction variables in any arguments strings, including the .I action argument, at the time it is called using the construction variables in the .B env construction environment through which .BR env.Builder () was called. The .BR Builder () form delays all variable expansion until after the Builder object is actually called. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI CacheDir( cache_dir ) .TP .RI env.CacheDir( cache_dir ) Specifies that .B scons will maintain a cache of derived files in .I cache_dir . The derived files in the cache will be shared among all the builds using the same .BR CacheDir () call. When a .BR CacheDir () is being used and .B scons finds a derived file that needs to be rebuilt, it will first look in the cache to see if a derived file has already been built from identical input files and an identical build action (as incorporated into the MD5 build signature). If so, .B scons will retrieve the file from the cache. If the derived file is not present in the cache, .B scons will rebuild it and then place a copy of the built file in the cache (identified by its MD5 build signature), so that it may be retrieved by other builds that need to build the same derived file from identical inputs. Use of a specified .BR CacheDir() may be disabled for any invocation by using the .B --cache-disable option. If the .B --cache-force option is used, .B scons will place a copy of .I all derived files in the cache, even if they already existed and were not built by this invocation. This is useful to populate a cache the first time .BR CacheDir () is added to a build, or after using the .B --cache-disable option. When using .BR CacheDir (), .B scons will report, "Retrieved `file' from cache," unless the .B --cache-show option is being used. When the .B --cache-show option is used, .B scons will print the action that .I would have been used to build the file, without any indication that the file was actually retrieved from the cache. This is useful to generate build logs that are equivalent regardless of whether a given derived file has been built in-place or retrieved from the cache. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Clean( targets ", " files_or_dirs ) .TP .RI env.Clean( targets ", " files_or_dirs ) This specifies a list of files or directories which should be removed whenever the targets are specified with the .B -c command line option. The specified targets may be a list or an individual target. Multiple calls to .BR Clean () are legal, and create new targets or add files and directories to the clean list for the specified targets. Multiple files or directories should be specified either as separate arguments to the .BR Clean () method, or as a list. .BR Clean () will also accept the return value of any of the construction environment Builder methods. Examples: The related .BR NoClean () function overrides calling .BR Clean () for the same target, and any targets passed to both functions will .I not be removed by the .B -c option. Examples: .ES Clean('foo', ['bar', 'baz']) Clean('dist', env.Program('hello', 'hello.c')) Clean(['foo', 'bar'], 'something_else_to_clean') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Command( target ", " source ", " action ", [" key = val ", ...])" .TP .RI env.Command( target ", " source ", " action ", [" key = val ", ...])" Executes a specific action (or list of actions) to build a target file or files. This is more convenient than defining a separate Builder object for a single special-case build. As a special case, the .B source_scanner keyword argument can be used to specify a Scanner object that will be used to scan the sources. (The global .B DirScanner object can be used if any of the sources will be directories that must be scanned on-disk for changes to files that aren't already specified in other Builder of function calls.) Any other keyword arguments specified override any same-named existing construction variables. An action can be an external command, specified as a string, or a callable Python object; see "Action Objects," below, for more complete information. Also note that a string specifying an external command may be preceded by an .B @ (at-sign) to suppress printing the command in question, or by a .B \- (hyphen) to ignore the exit status of the external command. Examples: .ES env.Command('foo.out', 'foo.in', "$FOO_BUILD < $SOURCES > $TARGET") env.Command('bar.out', 'bar.in', ["rm -f $TARGET", "$BAR_BUILD < $SOURCES > $TARGET"], ENV = {'PATH' : '/usr/local/bin/'}) def rename(env, target, source): import os os.rename('.tmp', str(target[0])) env.Command('baz.out', 'baz.in', ["$BAZ_BUILD < $SOURCES > .tmp", rename ]) .EE Note that the .BR Command () function will usually assume, by default, that the specified targets and/or sources are Files, if no other part of the configuration identifies what type of entry it is. If necessary, you can explicitly specify that targets or source nodes should be treated as directoriese by using the .BR Dir () or .BR env.Dir () functions: .ES env.Command('ddd.list', Dir('ddd'), 'ls -l $SOURCE > $TARGET') env['DISTDIR'] = 'destination/directory' env.Command(env.Dir('$DISTDIR')), None, make_distdir) .EE (Also note that SCons will usually automatically create any directory necessary to hold a target file, so you normally don't need to create directories by hand.) '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Configure( env ", [" custom_tests ", " conf_dir ", " log_file ", " config_h ]) .TP .RI env.Configure([ custom_tests ", " conf_dir ", " log_file ", " config_h ]) Creates a Configure object for integrated functionality similar to GNU autoconf. See the section "Configure Contexts," below, for a complete explanation of the arguments and behavior. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Clone([ key = val ", ...])" Return a separate copy of a construction environment. If there are any keyword arguments specified, they are added to the returned copy, overwriting any existing values for the keywords. .ES env2 = env.Clone() env3 = env.Clone(CCFLAGS = '-g') .EE .IP Additionally, a list of tools and a toolpath may be specified, as in the Environment constructor: .ES def MyTool(env): env['FOO'] = 'bar' env4 = env.Clone(tools = ['msvc', MyTool]) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Copy([ key = val ", ...])" A synonym for env.Clone(). (This will probably be officially deprecated some day.) '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.CVS( repository ", " module ) A factory function that returns a Builder object to be used to fetch source files from the specified CVS .IR repository . The returned Builder is intended to be passed to the .B SourceCode function. The optional specified .I module will be added to the beginning of all repository path names; this can be used, in essence, to strip initial directory names from the repository path names, so that you only have to replicate part of the repository directory hierarchy in your local build directory: .ES # Will fetch foo/bar/src.c # from /usr/local/CVSROOT/foo/bar/src.c. env.SourceCode('.', env.CVS('/usr/local/CVSROOT')) # Will fetch bar/src.c # from /usr/local/CVSROOT/foo/bar/src.c. env.SourceCode('.', env.CVS('/usr/local/CVSROOT', 'foo')) # Will fetch src.c # from /usr/local/CVSROOT/foo/bar/src.c. env.SourceCode('.', env.CVS('/usr/local/CVSROOT', 'foo/bar')) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Default( targets ) .TP .RI env.Default( targets ) This specifies a list of default targets, which will be built by .B scons if no explicit targets are given on the command line. Multiple calls to .BR Default () are legal, and add to the list of default targets. Multiple targets should be specified as separate arguments to the .BR Default () method, or as a list. .BR Default () will also accept the Node returned by any of a construction environment's builder methods. Examples: .ES Default('foo', 'bar', 'baz') env.Default(['a', 'b', 'c']) hello = env.Program('hello', 'hello.c') env.Default(hello) .EE .IP An argument to .BR Default () of .B None will clear all default targets. Later calls to .BR Default () will add to the (now empty) default-target list like normal. The current list of targets added using the .BR Default () function or method is available in the .B DEFAULT_TARGETS list; see below. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI DefaultEnvironment([ args ]) Creates and returns a default construction environment object. This construction environment is used internally by SCons in order to execute many of the global functions in this list, and to fetch source files transparently from source code management systems. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Depends( target ", " dependency ) .TP .RI env.Depends( target ", " dependency ) Specifies an explicit dependency; the target file(s) will be rebuilt whenever the dependency file(s) has changed. This should only be necessary for cases where the dependency is not caught by a Scanner for the file. .ES env.Depends('foo', 'other-input-file-for-foo') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Dictionary([ vars ]) Returns a dictionary object containing copies of all of the construction variables in the environment. If there are any variable names specified, only the specified construction variables are returned in the dictionary. .ES dict = env.Dictionary() cc_dict = env.Dictionary('CC', 'CCFLAGS', 'CCCOM') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Dir( name ", [" directory ]) .TP .RI env.Dir( name ", [" directory ]) This returns a Directory Node, an object that represents the specified directory .IR name . .I name can be a relative or absolute path. .I directory is an optional directory that will be used as the parent directory. If no .I directory is specified, the current script's directory is used as the parent. Directory Nodes can be used anywhere you would supply a string as a directory name to a Builder method or function. Directory Nodes have attributes and methods that are useful in many situations; see "File and Directory Nodes," below. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Dump([ key ]) Returns a pretty printable representation of the environment. .IR key , if not .IR None , should be a string containing the name of the variable of interest. This SConstruct: .ES env=Environment() print env.Dump('CCCOM') .EE will print: .ES '$CC $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES' .EE .ES env=Environment() print env.Dump() .EE will print: .ES { 'AR': 'ar', 'ARCOM': '$AR $ARFLAGS $TARGET $SOURCES\n$RANLIB $RANLIBFLAGS $TARGET', 'ARFLAGS': ['r'], 'AS': 'as', 'ASCOM': '$AS $ASFLAGS -o $TARGET $SOURCES', 'ASFLAGS': [], ... .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI EnsurePythonVersion( major ", " minor ) .TP .RI env.EnsurePythonVersion( major ", " minor ) Ensure that the Python version is at least .IR major . minor . This function will print out an error message and exit SCons with a non-zero exit code if the actual Python version is not late enough. .ES EnsurePythonVersion(2,2) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI EnsureSConsVersion( major ", " minor ", [" revision ]) .TP .RI env.EnsureSConsVersion( major ", " minor ", [" revision ]) Ensure that the SCons version is at least .IR major.minor , or .IR major.minor.revision . if .I revision is specified. This function will print out an error message and exit SCons with a non-zero exit code if the actual SCons version is not late enough. .ES EnsureSConsVersion(0,14) EnsureSConsVersion(0,96,90) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Environment([ key = value ", ...])" .TP .RI env.Environment([ key = value ", ...])" Return a new construction environment initialized with the specified .IR key = value pairs. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Execute( action ", [" strfunction ", " varlist ]) .TP .RI env.Execute( action ", [" strfunction ", " varlist ]) Executes an Action object. The specified .IR action may be an Action object (see the section "Action Objects," below, for a complete explanation of the arguments and behavior), or it may be a command-line string, list of commands, or executable Python function, each of which will be converted into an Action object and then executed. The exit value of the command or return value of the Python function will be returned. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Exit([ value ]) .TP .RI env.Exit([ value ]) This tells .B scons to exit immediately with the specified .IR value . A default exit value of .B 0 (zero) is used if no value is specified. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Export( vars ) .TP .RI env.Export( vars ) This tells .B scons to export a list of variables from the current SConscript file to all other SConscript files. The exported variables are kept in a global collection, so subsequent calls to .BR Export () will over-write previous exports that have the same name. Multiple variable names can be passed to .BR Export () as separate arguments or as a list. A dictionary can be used to map variables to a different name when exported. Both local variables and global variables can be exported. Examples: .ES env = Environment() # Make env available for all SConscript files to Import(). Export("env") package = 'my_name' # Make env and package available for all SConscript files:. Export("env", "package") # Make env and package available for all SConscript files: Export(["env", "package"]) # Make env available using the name debug:. Export({"debug":env}) .EE .IP Note that the .BR SConscript () function supports an .I exports argument that makes it easier to to export a variable or set of variables to a single SConscript file. See the description of the .BR SConscript () function, below. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI File( name ", [" directory ]) .TP .RI env.File( name ", [" directory ]) This returns a File Node, an object that represents the specified file .IR name . .I name can be a relative or absolute path. .I directory is an optional directory that will be used as the parent directory. File Nodes can be used anywhere you would supply a string as a file name to a Builder method or function. File Nodes have attributes and methods that are useful in many situations; see "File and Directory Nodes," below. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI FindFile( file ", " dirs ) .TP .RI env.FindFile( file ", " dirs ) Search for .I file in the path specified by .IR dirs . .I file may be a list of file names or a single file name. In addition to searching for files that exist in the filesytem, this function also searches for derived files that have not yet been built. .ES foo = env.FindFile('foo', ['dir1', 'dir2']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Flatten( sequence ) .TP .RI env.Flatten( sequence ) Takes a sequence (that is, a Python list or tuple) that may contain nested sequences and returns a flattened list containing all of the individual elements in any sequence. This can be helpful for collecting the lists returned by calls to Builders; other Builders will automatically flatten lists specified as input, but direct Python manipulation of these lists does not: .ES foo = Object('foo.c') bar = Object('bar.c') # Because `foo' and `bar' are lists returned by the Object() Builder, # `objects' will be a list containing nested lists: objects = ['f1.o', foo, 'f2.o', bar, 'f3.o'] # Passing such a list to another Builder is all right because # the Builder will flatten the list automatically: Program(source = objects) # If you need to manipulate the list directly using Python, you need to # call Flatten() yourself, or otherwise handle nested lists: for object in Flatten(objects): print str(object) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI GetBuildPath( file ", [" ... ]) .TP .RI env.GetBuildPath( file ", [" ... ]) Returns the .B scons path name (or names) for the specified .I file (or files). The specified .I file or files may be .B scons Nodes or strings representing path names. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI GetLaunchDir() .TP .RI env.GetLaunchDir() Returns the absolute path name of the directory from which .B scons was initially invoked. This can be useful when using the .BR \-u , .BR \-U or .BR \-D options, which internally change to the directory in which the .B SConstruct file is found. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI GetOption( name ) .TP .RI env.GetOption( name ) This function provides a way to query a select subset of the scons command line options from a SConscript file. See .IR SetOption () for a description of the options available. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" '\".TP '\".RI GlobalBuilders( flag ) '\"When '\".B flag '\"is non-zero, '\"adds the names of the default builders '\"(Program, Library, etc.) '\"to the global name space '\"so they can be called without an explicit construction environment. '\"(This is the default.) '\"When '\".B '\"flag is zero, '\"the names of the default builders are removed '\"from the global name space '\"so that an explicit construction environment is required '\"to call all builders. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Help( text ) .TP .RI env.Help( text ) This specifies help text to be printed if the .B -h argument is given to .BR scons . If .BR Help is called multiple times, the text is appended together in the order that .BR Help is called. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Ignore( target ", " dependency ) .TP .RI env.Ignore( target ", " dependency ) The specified dependency file(s) will be ignored when deciding if the target file(s) need to be rebuilt. .ES env.Ignore('foo', 'foo.c') env.Ignore('bar', ['bar1.h', 'bar2.h']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Import( vars ) .TP .RI env.Import( vars ) This tells .B scons to import a list of variables into the current SConscript file. This will import variables that were exported with .BR Export () or in the .I exports argument to .BR SConscript (). Variables exported by .BR SConscript () have precedence. Multiple variable names can be passed to .BR Import () as separate arguments or as a list. The variable "*" can be used to import all variables. Examples: .ES Import("env") Import("env", "variable") Import(["env", "variable"]) Import("*") .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Install( dir ", " source ) .TP .RI env.Install( dir ", " source ) Installs one or more source files or directories in a destination directory .IR dir . The names of the specified source files or directories remain the same within the destination directory. .ES env.Install(dir = '/usr/local/bin', source = ['foo', 'bar']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI InstallAs( target ", " source ) .TP .RI env.InstallAs( target ", " source ) Installs one or more source files or directories to specific names, allowing changing a file or directory name as part of the installation. It is an error if the .I target and .I source arguments list different numbers of files or directories. .ES env.InstallAs(target = '/usr/local/bin/foo', source = 'foo_debug') env.InstallAs(target = ['../lib/libfoo.a', '../lib/libbar.a'], source = ['libFOO.a', 'libBAR.a']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Literal( string ) .TP .RI env.Literal( string ) The specified .I string will be preserved as-is and not have construction variables expanded. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Local( targets ) .TP .RI env.Local( targets ) The specified .I targets will have copies made in the local tree, even if an already up-to-date copy exists in a repository. Returns a list of the target Node or Nodes. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.MergeFlags( arg ", [" unique ]) Merges the specified .I arg values to the construction envrionment's construction variables. If the .I arg argument is not a dictionary, it is converted to one by calling .B env.ParseFlags() on the argument before the values are merged. Note that .I arg must be a single value, so multiple strings must be passed in as a list, not as separate arguments to .BR env.MergeFlags (). By default, duplicate values are eliminated; you can, however, specify .B unique=0 to allow duplicate values to be added. When eliminating duplicate values, any construction variables that end with the string .B PATH keep the left-most unique value. All other construction variables keep the right-most unique value. Examples: .ES # Add an optimization flag to $CCFLAGS. env.MergeFlags('-O3') # Combine the flags returned from running pkg-config with an optimization # flag and merge the result into the construction variables. env.MergeFlags(['!pkg-config gtk+-2.0 --cflags', '-O3']) env.MergeFlags(['-O3', '!pkg-config gtk+-2.0 --cflags --libs', '!pkg-config libpng12 --cflags --libs']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI NoClean( target ", ...)" .TP .RI env.NoClean( target ", ...)" Specifies a list of files or directories which should .I not be removed whenever the targets (or their dependencies) are specified with the .B -c command line option. The specified targets may be a list or an individual target. Multiple calls to .BR NoClean () are legal, and prevent each specified target from being removed by calls to the .B -c option. Multiple files or directories should be specified either as separate arguments to the .BR NoClean () method, or as a list. .BR NoClean () will also accept the return value of any of the construction environment Builder methods. Calling .BR NoClean () for a target overrides calling .BR Clean () for the same target, and any targets passed to both functions will .I not be removed by the .B -c option. Examples: .ES NoClean('foo.elf') NoClean(env.Program('hello', 'hello.c')) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.ParseConfig( command ", [" function ", " unique ]) Calls the specified .I function to modify the environment as specified by the output of .I command . The default .I function is .BR env.MergeFlags (), which expects the output of a typical .I *-config command (for example, .BR gtk-config ) and adds the options to the appropriate construction variables. By default, duplicate values are not added to any construction variables; you can specify .B unique=0 to allow duplicate values to be added. Interpreted options and the construction variables they affect are as specified for the .BR env.ParseFlags () method (which thie method calls). See that method's description, below, for a table of options and construction variables. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI ParseDepends( filename ", [" must_exist ]) .TP .RI env.ParseDepends( filename ", [" must_exist " " only_one ]) Parses the contents of the specified .I filename as a list of dependencies in the style of .BR Make or .BR mkdep , and explicitly establishes all of the listed dependencies. By default, it is not an error if the specified .I filename does not exist. The optional .I must_exit argument may be set to a non-zero value to have scons throw an exception and generate an error if the file does not exist, or is otherwise inaccessible. The optional .I only_one argument may be set to a non-zero value to have scons thrown an exception and generate an error if the file contains dependency information for more than one target. This can provide a small sanity check for files intended to be generated by, for example, the .B gcc -M flag, which should typically only write dependency information for one output file into a corresponding .B .d file. The .I filename and all of the files listed therein will be interpreted relative to the directory of the .I SConscript file which calls the .B ParseDepends function. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.ParseFlags( flags ", ...)" Parses one or more strings containing typical command-line flags for GCC tool chains and returns a dictionary with the flag values separated into the appropriate SCons construction variables. This is intended as a companion to the .BR env.MergeFlags () method, but allows for the values in the returned dictionary to be modified, if necessary, before merging them into the construction environment. (Note that .BR env.MergeFlags () will call this method if its argument is not a dictionary, so it is usually not necessary to call .BR env.ParseFlags () directly unless you want to manipulate the values.) If the first character in any string is an exclamation mark (!), the rest of the string is executed as a command, and the output from the command is parsed as GCC tool chain command-line flags and added to the resulting dictionary. Flag values are translated accordig to the prefix found, and added to the following construction variables: .ES -arch CCFLAGS, LINKFLAGS -D CPPDEFINES -framework FRAMEWORKS -frameworkdir= FRAMEWORKPATH -include CCFLAGS -isysroot CCFLAGS, LINKFLAGS -I CPPPATH -l LIBS -L LIBPATH -mno-cygwin CCFLAGS, LINKFLAGS -mwindows LINKFLAGS -pthread CCFLAGS, LINKFLAGS -Wa, ASFLAGS, CCFLAGS -Wl,-rpath= RPATH -Wl,-R, RPATH -Wl,-R RPATH -Wl, LINKFLAGS -Wp, CPPFLAGS - CCFLAGS + CCFLAGS, LINKFLAGS .EE Any other strings not associated with options are assumed to be the names of libraries and added to the .B LIBS construction variable. Examples (all of which produce the same result): .ES dict = env.ParseFlags('-O2 -Dfoo -Dbar=1') dict = env.ParseFlags('-O2', '-Dfoo', '-Dbar=1') dict = env.ParseFlags(['-O2', '-Dfoo -Dbar=1']) dict = env.ParseFlags('-O2', '!echo -Dfoo -Dbar=1') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP env.Perforce() A factory function that returns a Builder object to be used to fetch source files from the Perforce source code management system. The returned Builder is intended to be passed to the .B SourceCode function: .ES env.SourceCode('.', env.Perforce()) .EE .IP Perforce uses a number of external environment variables for its operation. Consequently, this function adds the following variables from the user's external environment to the construction environment's ENV dictionary: P4CHARSET, P4CLIENT, P4LANGUAGE, P4PASSWD, P4PORT, P4USER, SYSTEMROOT, USER, and USERNAME. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Platform( string ) Returns a callable object that can be used to initialize a construction environment using the platform keyword of the Environment() method: .ES env = Environment(platform = Platform('win32')) .EE .TP .RI env.Platform( string ) Applies the callable object for the specified platform .I string to the environment through which the method was called. .ES env.Platform('posix') .EE .IP Note that the .B win32 platform adds the .B SYSTEMDRIVE and .B SYSTEMROOT variables from the user's external environment to the construction environment's .B ENV dictionary. This is so that any executed commands that use sockets to connect with other systems (such as fetching source files from external CVS repository specifications like .BR :pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons ) will work on Windows systems. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Precious( target ", ...)" .TP .RI env.Precious( target ", ...)" Marks each given .I target as precious so it is not deleted before it is rebuilt. Normally .B scons deletes a target before building it. Multiple targets can be passed in to a single call to .BR Precious (). '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Prepend( key = val ", [...])" Appends the specified keyword arguments to the beginning of construction variables in the environment. If the Environment does not have the specified construction variable, it is simply added to the environment. If the values of the construction variable and the keyword argument are the same type, then the two values will be simply added together. Otherwise, the construction variable and the value of the keyword argument are both coerced to lists, and the lists are added together. (See also the Append method, above.) .ES env.Prepend(CCFLAGS = '-g ', FOO = ['foo.yyy']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.PrependENVPath( name ", " newpath ", [" envname ", " sep ]) This appends new path elements to the given path in the specified external environment .RB ( ENV by default). This will only add any particular path once (leaving the first one it encounters and ignoring the rest, to preserve path order), and to help assure this, will normalize all paths (using .B os.path.normpath and .BR os.path.normcase ). This can also handle the case where the given old path variable is a list instead of a string, in which case a list will be returned instead of a string. Example: .ES print 'before:',env['ENV']['INCLUDE'] include_path = '/foo/bar:/foo' env.PrependENVPath('INCLUDE', include_path) print 'after:',env['ENV']['INCLUDE'] yields: before: /biz:/foo after: /foo/bar:/foo:/biz .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.PrependUnique( key = val ", [...])" Appends the specified keyword arguments to the beginning of construction variables in the environment. If the Environment does not have the specified construction variable, it is simply added to the environment. If the construction variable being appended to is a list, then any value(s) that already exist in the construction variable will .I not be added again to the list. .ES env.PrependUnique(CCFLAGS = '-g', FOO = ['foo.yyy']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP env.RCS() A factory function that returns a Builder object to be used to fetch source files from RCS. The returned Builder is intended to be passed to the .B SourceCode function: .ES env.SourceCode('.', env.RCS()) .EE .IP Note that .B scons will fetch source files from RCS subdirectories automatically, so configuring RCS as demonstrated in the above example should only be necessary if you are fetching from RCS,v files in the same directory as the source files, or if you need to explicitly specify RCS for a specific subdirectory. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.Replace( key = val ", [...])" Replaces construction variables in the Environment with the specified keyword arguments. .ES env.Replace(CCFLAGS = '-g', FOO = 'foo.xxx') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Repository( directory ) .TP .RI env.Repository( directory ) Specifies that .I directory is a repository to be searched for files. Multiple calls to .BR Repository () are legal, and each one adds to the list of repositories that will be searched. To .BR scons , a repository is a copy of the source tree, from the top-level directory on down, which may contain both source files and derived files that can be used to build targets in the local source tree. The canonical example would be an official source tree maintained by an integrator. If the repository contains derived files, then the derived files should have been built using .BR scons , so that the repository contains the necessary signature information to allow .B scons to figure out when it is appropriate to use the repository copy of a derived file, instead of building one locally. Note that if an up-to-date derived file already exists in a repository, .B scons will .I not make a copy in the local directory tree. In order to guarantee that a local copy will be made, use the .B Local() method. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Return( vars ) This tells .B scons what variable(s) to use as the return value(s) of the current SConscript file. These variables will be returned to the "calling" SConscript file as the return value(s) of .BR SConscript (). Multiple variable names should be passed to .BR Return () as a list. Example: .ES Return("foo") Return(["foo", "bar"]) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Scanner( function ", [" argument ", " keys ", " path_function ", " node_class ", " node_factory ", " scan_check ", " recursive ]) .TP .RI env.Scanner( function ", [" argument ", " keys ", " path_function ", " node_class ", " node_factory ", " scan_check ", " recursive ]) Creates a Scanner object for the specified .IR function . See the section "Scanner Objects," below, for a complete explanation of the arguments and behavior. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP env.SCCS() A factory function that returns a Builder object to be used to fetch source files from SCCS. The returned Builder is intended to be passed to the .B SourceCode function: .ES env.SourceCode('.', env.SCCS()) .EE .IP Note that .B scons will fetch source files from SCCS subdirectories automatically, so configuring SCCS as demonstrated in the above example should only be necessary if you are fetching from .I s.SCCS files in the same directory as the source files, or if you need to explicitly specify SCCS for a specific subdirectory. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SConscript( scripts ", [" exports ", " build_dir ", " src_dir ", " duplicate ]) .TP .RI env.SConscript( scripts ", [" exports ", " build_dir ", " src_dir ", " duplicate ]) .TP .RI SConscript(dirs= subdirs ", [name=" script ", " exports ", " build_dir ", " src_dir ", " duplicate ]) .TP .RI env.SConscript(dirs= subdirs ", [name=" script ", " exports ", " build_dir ", " src_dir ", " duplicate ]) This tells .B scons to execute one or more subsidiary SConscript (configuration) files. There are two ways to call the .BR SConscript () function. The first way you can call .BR SConscript () is to explicitly specify one or more .I scripts as the first argument. A single script may be specified as a string; multiple scripts must be specified as a list (either explicitly or as created by a function like .BR Split ()). The second way you can call .BR SConscript () is to specify a list of (sub)directory names as a .RI dirs= subdirs keyword argument. In this case, .B scons will, by default, execute a subsidiary configuration file named .B SConscript in each of the specified directories. You may specify a name other than .B SConscript by supplying an optional .RI name= script keyword argument. The optional .I exports argument provides a list of variable names or a dictionary of named values to export to the .IR script(s) ". " These variables are locally exported only to the specified .IR script(s) , and do not affect the global pool of variables used by the .BR Export () function. '\"If multiple dirs are provided, '\"each script gets a fresh export. The subsidiary .I script(s) must use the .BR Import () function to import the variables. The optional .I build_dir argument specifies that all of the target files (for example, object files and executables) that would normally be built in the subdirectory in which .I script resides should actually be built in .IR build_dir . .I build_dir is interpreted relative to the directory of the calling SConscript file. The optional .I src_dir argument specifies that the source files from which the target files should be built can be found in .IR src_dir . .I src_dir is interpreted relative to the directory of the calling SConscript file. By default, .B scons will link or copy (depending on the platform) all the source files into the build directory. This behavior may be disabled by setting the optional .I duplicate argument to 0 (it is set to 1 by default), in which case .B scons will refer directly to the source files in their source directory when building target files. (Setting .IR duplicate =0 is usually safe, and always more efficient than the default of .IR duplicate =1, but it may cause build problems in certain end-cases, such as compiling from source files that are generated by the build.) Any variables returned by .I script using .BR Return () will be returned by the call to .BR SConscript (). Examples: .ES SConscript('subdir/SConscript') foo = SConscript('sub/SConscript', exports='env') SConscript('dir/SConscript', exports=['env', 'variable']) SConscript('src/SConscript', build_dir='build', duplicate=0) SConscript('bld/SConscript', src_dir='src', exports='env variable') SConscript(dirs=['sub1', 'sub2']) SConscript(dirs=['sub3', 'sub4'], name='MySConscript') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SConscriptChdir( value ) .TP .RI env.SConscriptChdir( value ) By default, .B scons changes its working directory to the directory in which each subsidiary SConscript file lives. This behavior may be disabled by specifying either: .ES SConscriptChdir(0) env.SConscriptChdir(0) .EE .IP in which case .B scons will stay in the top-level directory while reading all SConscript files. (This may be necessary when building from repositories, when all the directories in which SConscript files may be found don't necessarily exist locally.) You may enable and disable this ability by calling SConscriptChdir() multiple times: .ES env = Environment() SConscriptChdir(0) SConscript('foo/SConscript') # will not chdir to foo env.SConscriptChdir(1) SConscript('bar/SConscript') # will chdir to bar .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SConsignFile([ file , dbm_module ]) .TP .RI env.SConsignFile([ file , dbm_module ]) This tells .B scons to store all file signatures in the specified database .IR file . If the .I file name is omitted, .B .sconsign is used by default. (The actual file name(s) stored on disk may have an appropriated suffix appended by the .IR dbm_module .) If .I file is not an absolute path name, the file is placed in the same directory as the top-level .B SConstruct file. If .I file is .BR None , then .B scons will store file signatures in a separate .B .sconsign file in each directory, not in one global database file. (This was the default behavior prior to SCons 0.96.91 and 0.97.) The optional .I dbm_module argument can be used to specify which Python database module The default is to use a custom .B SCons.dblite module that uses pickled Python data structures, and which works on all Python versions from 1.5.2 on. Examples: .ES # Explicitly stores signatures in ".sconsign.dblite" # in the top-level SConstruct directory (the # default behavior). SConsignFile() # Stores signatures in the file "etc/scons-signatures" # relative to the top-level SConstruct directory. SConsignFile("etc/scons-signatures") # Stores signatures in the specified absolute file name. SConsignFile("/home/me/SCons/signatures") # Stores signatures in a separate .sconsign file # in each directory. SConsignFile(None) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.SetDefault(key = val ", [...])" Sets construction variables to default values specified with the keyword arguments if (and only if) the variables are not already set. The following statements are equivalent: .ES env.SetDefault(FOO = 'foo') if not env.has_key('FOO'): env['FOO'] = 'foo' .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SetOption( name ", " value ) .TP .RI env.SetOption( name ", " value ) This function provides a way to set a select subset of the scons command line options from a SConscript file. The options supported are: .B clean which corresponds to -c, --clean, and --remove; .B duplicate which corresponds to --duplicate; .B implicit_cache which corresponds to --implicit-cache; .B max_drift which corresponds to --max-drift; .B num_jobs which corresponds to -j and --jobs. See the documentation for the corresponding command line object for information about each specific option. Example: .ES SetOption('max_drift', 1) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SideEffect( side_effect ", " target ) .TP .RI env.SideEffect( side_effect ", " target ) Declares .I side_effect as a side effect of building .IR target . Both .I side_effect and .I target can be a list, a file name, or a node. A side effect is a target that is created as a side effect of building other targets. For example, a Windows PDB file is created as a side effect of building the .obj files for a static library. If a target is a side effect of multiple build commands, .B scons will ensure that only one set of commands is executed at a time. Consequently, you only need to use this method for side-effect targets that are built as a result of multiple build commands. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SourceCode( entries ", " builder ) .TP .RI env.SourceCode( entries ", " builder ) Arrange for non-existent source files to be fetched from a source code management system using the specified .IR builder . The specified .I entries may be a Node, string or list of both, and may represent either individual source files or directories in which source files can be found. For any non-existent source files, .B scons will search up the directory tree and use the first .B SourceCode builder it finds. The specified .I builder may be .BR None , in which case .B scons will not use a builder to fetch source files for the specified .IR entries , even if a .B SourceCode builder has been specified for a directory higher up the tree. .B scons will, by default, fetch files from SCCS or RCS subdirectories without explicit configuration. This takes some extra processing time to search for the necessary source code management files on disk. You can avoid these extra searches and speed up your build a little by disabling these searches as follows: .ES env.SourceCode('.', None) .EE .IP Note that if the specified .I builder is one you create by hand, it must have an associated construction environment to use when fetching a source file. .B scons provides a set of canned factory functions that return appropriate Builders for various popular source code management systems. Canonical examples of invocation include: .ES env.SourceCode('.', env.BitKeeper('/usr/local/BKsources')) env.SourceCode('src', env.CVS('/usr/local/CVSROOT')) env.SourceCode('/', env.RCS()) env.SourceCode(['f1.c', 'f2.c'], env.SCCS()) env.SourceCode('no_source.c', None) .EE '\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion')) '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI env.subst( string ", [" raw ", " target ", " source ", " conv ]) Performs construction variable interpolation on the specified string argument. By default, leading or trailing white space will be removed from the result. and all sequences of white space will be compressed to a single space character. Additionally, any .B $( and .B $) character sequences will be stripped from the returned string, The optional .I raw argument may be set to .B 1 if you want to preserve white space and .BR $( - $) sequences. The .I raw argument may be set to .B 2 if you want to strip all characters between any .B $( and .B $) pairs (as is done for signature calculation). The optional .I target and .I source keyword arguments must be set to lists of target and source nodes, respectively, if you want the .BR $TARGET , .BR $TARGETS , .BR $SOURCE and .BR $SOURCES to be available for expansion. This is usually necessary if you are calling .BR env.subst () from within a Python function used as an SCons action. By default, all returned values are converted to their string representation. The optional .I conv argument may specify a conversion function that will be used in place of the default. For example, if you want Python objects (including SCons Nodes) to be returned as Python objects, you can use the Python .B lambda idiom to pass in an unnamed function that simply returns its unconverted argument. .ES print env.subst("The C compiler is: $CC") def compile(target, source, env): sourceDir = env.subst("${SOURCE.srcdir}", target=target, source=source) source_nodes = env.subst('$EXPAND_TO_NODELIST', conv=lambda x: x) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" '\".TP '\".RI Subversion( repository ", " module ) '\"A factory function that '\"returns a Builder object '\"to be used to fetch source files '\"from the specified Subversion '\".IR repository . '\"The returned Builder '\"is intended to be passed to the '\".B SourceCode '\"function. '\" '\"The optional specified '\".I module '\"will be added to the beginning '\"of all repository path names; '\"this can be used, in essence, '\"to strip initial directory names '\"from the repository path names, '\"so that you only have to '\"replicate part of the repository '\"directory hierarchy in your '\"local build directory: '\" '\".ES '\"# Will fetch foo/bar/src.c '\"# from /usr/local/Subversion/foo/bar/src.c. '\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion')) '\" '\"# Will fetch bar/src.c '\"# from /usr/local/Subversion/foo/bar/src.c. '\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion', 'foo')) '\" '\"# Will fetch src.c '\"# from /usr/local/Subversion/foo/bar/src.c. '\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion', 'foo/bar')) '\".EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI SourceSignatures( type ) .TP .RI env.SourceSignatures( type ) This function tells SCons what type of signature to use for source files: .B "MD5" or .BR "timestamp" . If the environment method is used, the specified type of source signature is only used when deciding whether targets built with that environment are up-to-date or must be rebuilt. If the global function is used, the specified type of source signature becomes the default used for all decisions about whether targets are up-to-date. "MD5" means the signature of a source file is the MD5 checksum of its contents. "timestamp" means the signature of a source file is its timestamp (modification time). There is no different between the two behaviors for Python .BR Value () node objects. "MD5" signatures take longer to compute, but are more accurate than "timestamp" signatures. The default is "MD5". '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Split( arg ) .TP .RI env.Split( arg ) Returns a list of file names or other objects. If arg is a string, it will be split on strings of white-space characters within the string, making it easier to write long lists of file names. If arg is already a list, the list will be returned untouched. If arg is any other type of object, it will be returned as a list containing just the object. .ES files = Split("f1.c f2.c f3.c") files = env.Split("f4.c f5.c f6.c") files = Split(""" f7.c f8.c f9.c """) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI TargetSignatures( type ) .TP .RI env.TargetSignatures( type ) This function tells SCons what type of signatures to use for target files: .B "build" or .BR "content" . If the environment method is used, the specified type of signature is only used for targets built with that environment. If the global function is used, the specified type of signature becomes the default used for all target files that don't have an explicit target signature type specified for their environments. "build" means the signature of a target file is made by concatenating all of the signatures of all its source files. "content" means the signature of a target file is an MD5 checksum of its contents. "build" signatures are usually faster to compute, but "content" signatures can prevent unnecessary rebuilds when a target file is rebuilt to the exact same contents as the previous build. The default is "build". '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Tool( string [, toolpath ", " **kw ]) Returns a callable object that can be used to initialize a construction environment using the tools keyword of the Environment() method. The object may be called with a construction environment as an argument, in which case the object will add the necessary variables to the construction environment and the name of the tool will be added to the .B $TOOLS construction variable. Additional keyword arguments are passed to the tool's .B generate() method. .ES env = Environment(tools = [ Tool('msvc') ]) env = Environment() t = Tool('msvc') t(env) # adds 'msvc' to the TOOLS variable u = Tool('opengl', toolpath = ['tools']) u(env) # adds 'opengl' to the TOOLS variable .EE .TP .RI env.Tool( string [, toolpath ", " **kw ]) Applies the callable object for the specified tool .I string to the environment through which the method was called. Additional keyword arguments are passed to the tool's .B generate() method. .ES env.Tool('gcc') env.Tool('opengl', toolpath = ['build/tools']) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI Value( value ", [" built_value ]) .TP .RI env.Value( value ", [" built_value ]) Returns a Node object representing the specified Python value. Value Nodes can be used as dependencies of targets. If the result of calling .BR str( value ) changes between SCons runs, any targets depending on .BR Value( value ) will be rebuilt. When using timestamp source signatures, Value Nodes' timestamps are equal to the system time when the Node is created. The returned Value Node object has a .BR write () method that can be used to "build" a Value Node by setting a new value. The optional .I built_value argument can be specified when the Value Node is created to indicate the Node should already be considered "built." There is a corresponding .BR read () method that will return the built value of the Node. .ES def create(target, source, env): f = open(str(target[0]), 'wb') f.write('prefix=' + source[0].get_contents()) prefix = ARGUMENTS.get('prefix', '/usr/local') env = Environment() env['BUILDERS']['Config'] = Builder(action = create) env.Config(target = 'package-config', source = Value(prefix)) def build_value(target, source, env): target[0].write(source[0].get_contents()) output = env.Value('before') input = env.Value('after') env['BUILDERS']['UpdateValue'] = Builder(action = build_value) env.UpdateValue(target = Value(output), source = Value(input)) .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP .RI WhereIs( program ", [" path ", " pathext ", " reject ]) .TP .RI env.WhereIs( program ", [" path ", " pathext ", " reject ]) Searches for the specified executable .I program, returning the full path name to the program if it is found, and returning None if not. Searches the specified .I path, the value of the calling environment's PATH (env['ENV']['PATH']), or the user's current external PATH (os.environ['PATH']) by default. On Windows systems, searches for executable programs with any of the file extensions listed in the specified .I pathext, the calling environment's PATHEXT (env['ENV']['PATHEXT']) or the user's current PATHEXT (os.environ['PATHEXT']) by default. Will not select any path name or names in the specified .I reject list, if any. .SS SConscript Variables In addition to the global functions and methods, .B scons supports a number of Python variables that can be used in SConscript files to affect how you want the build to be performed. These variables may be accessed from custom Python modules that you import into an SConscript file by adding the following to the Python module: .ES from SCons.Script import * .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP ARGLIST A list .IR keyword = value arguments specified on the command line. Each element in the list is a tuple containing the .RI ( keyword , value ) of the argument. The separate .I keyword and .I value elements of the tuple can be accessed by subscripting for element .B [0] and .B [1] of the tuple, respectively. .ES print "first keyword, value =", ARGLIST[0][0], ARGLIST[0][1] print "second keyword, value =", ARGLIST[1][0], ARGLIST[1][1] third_tuple = ARGLIST[2] print "third keyword, value =", third_tuple[0], third_tuple[1] for key, value in ARGLIST: # process key and value .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP ARGUMENTS A dictionary of all the .IR keyword = value arguments specified on the command line. The dictionary is not in order, and if a given keyword has more than one value assigned to it on the command line, the last (right-most) value is the one in the .B ARGUMENTS dictionary. .ES if ARGUMENTS.get('debug', 0): env = Environment(CCFLAGS = '-g') else: env = Environment() .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP BUILD_TARGETS A list of the targets which .B scons will actually try to build, regardless of whether they were specified on the command line or via the .BR Default () function or method. The elements of this list may be strings .I or nodes, so you should run the list through the Python .B str function to make sure any Node path names are converted to strings. Because this list may be taken from the list of targets specified using the .BR Default () function or method, the contents of the list may change on each successive call to .BR Default (). See the .B DEFAULT_TARGETS list, below, for additional information. .ES if 'foo' in BUILD_TARGETS: print "Don't forget to test the `foo' program!" if 'special/program' in BUILD_TARGETS: SConscript('special') .EE .IP Note that the .B BUILD_TARGETS list only contains targets expected listed on the command line or via calls to the .BR Default () function or method. It does .I not contain all dependent targets that will be built as a result of making the sure the explicitly-specified targets are up to date. '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP COMMAND_LINE_TARGETS A list of the targets explicitly specified on the command line. If there are no targets specified on the command line, the list is empty. This can be used, for example, to take specific actions only when a certain target or targets is explicitly being built: .ES if 'foo' in COMMAND_LINE_TARGETS: print "Don't forget to test the `foo' program!" if 'special/program' in COMMAND_LINE_TARGETS: SConscript('special') .EE '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .TP DEFAULT_TARGETS A list of the target .I nodes that have been specified using the .BR Default () function or method. The elements of the list are nodes, so you need to run them through the Python .B str function to get at the path name for each Node. .ES print str(DEFAULT_TARGETS[0]) if 'foo' in map(str, DEFAULT_TARGETS): print "Don't forget to test the `foo' program!" .EE .IP The contents of the .B DEFAULT_TARGETS list change on on each successive call to the .BR Default () function: .ES print map(str, DEFAULT_TARGETS) # originally [] Default('foo') print map(str, DEFAULT_TARGETS) # now a node ['foo'] Default('bar') print map(str, DEFAULT_TARGETS) # now a node ['foo', 'bar'] Default(None) print map(str, DEFAULT_TARGETS) # back to [] .EE .IP Consequently, be sure to use .B DEFAULT_TARGETS only after you've made all of your .BR Default () calls, or else simply be careful of the order of these statements in your SConscript files so that you don't look for a specific default target before it's actually been added to the list. .SS Construction Variables .\" XXX From Gary Ruben, 23 April 2002: .\" I think it would be good to have an example with each construction .\" variable description in the documentation. .\" eg. .\" CC The C compiler .\" Example: env["CC"] = "c68x" .\" Default: env["CC"] = "cc" .\" .\" CCCOM The command line ... .\" Example: .\" To generate the compiler line c68x -ps -qq -mr -o $TARGET $SOURCES .\" env["CC"] = "c68x" .\" env["CFLAGS"] = "-ps -qq -mr" .\" env["CCCOM"] = "$CC $CFLAGS -o $TARGET $SOURCES .\" Default: .\" (I dunno what this is ;-) A construction environment has an associated dictionary of .I construction variables that are used by built-in or user-supplied build rules. Construction variables must follow the same rules for Python identifiers: the initial character must be an underscore or letter, followed by any number of underscores, letters, or digits. A number of useful construction variables are automatically defined by scons for each supported platform, and additional construction variables can be defined by the user. The following is a list of the automatically defined construction variables: '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" '\" BEGIN GENERATED CONSTRUCTION VARIABLE DESCRIPTIONS '\" '\" The descriptions below of the various SCons contruction variables '\" are generated from the .xml files that live next to the various '\" Python modules in the build enginer library. If you're reading '\" this [gnt]roff file with an eye towards patching this man page, '\" you can still submit a diff against this text, but it will have to '\" be translated to a diff against the underlying .xml file before the '\" patch is actually accepted. If you do that yourself, it will make '\" it easier to integrate the patch. '\" '\" BEGIN GENERATED CONSTRUCTION VARIABLE DESCRIPTIONS '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .so variables.man '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" '\" END GENERATED CONSTRUCTION VARIABLE DESCRIPTIONS '\" '\" The descriptions above of the various SCons contruction variables '\" are generated from the .xml files that live next to the various '\" Python modules in the build enginer library. If you're reading '\" this [gnt]roff file with an eye towards patching this man page, '\" you can still submit a diff against this text, but it will have to '\" be translated to a diff against the underlying .xml file before the '\" patch is actually accepted. If you do that yourself, it will make '\" it easier to integrate the patch. '\" '\" END GENERATED CONSTRUCTION VARIABLE DESCRIPTIONS '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" .LP Construction variables can be retrieved and set using the .B Dictionary method of the construction environment: .ES dict = env.Dictionary() dict["CC"] = "cc" .EE or using the [] operator: .ES env["CC"] = "cc" .EE Construction variables can also be passed to the construction environment constructor: .ES env = Environment(CC="cc") .EE or when copying a construction environment using the .B Clone method: .ES env2 = env.Clone(CC="cl.exe") .EE .SS Configure Contexts .B scons supports .I configure contexts, an integrated mechanism similar to the various AC_CHECK macros in GNU autoconf for testing for the existence of C header files, libraries, etc. In contrast to autoconf, .B scons does not maintain an explicit cache of the tested values, but uses its normal dependency tracking to keep the checked values up to date. However, users may override this behaviour with the .B --config command line option. The following methods can be used to perform checks: .TP .RI Configure( env ", [" custom_tests ", " conf_dir ", " log_file ", " config_h ]) .TP .RI env.Configure([ custom_tests ", " conf_dir ", " log_file ", " config_h ]) This creates a configure context, which can be used to perform checks. .I env specifies the environment for building the tests. This environment may be modified when performing checks. .I custom_tests is a dictionary containing custom tests. See also the section about custom tests below. By default, no custom tests are added to the configure context. .I conf_dir specifies a directory where the test cases are built. Note that this directory is not used for building normal targets. The default value is the directory #/.sconf_temp. .I log_file specifies a file which collects the output from commands that are executed to check for the existence of header files, libraries, etc. The default is the file #/config.log. If you are using the .B BuildDir method, you may want to specify a subdirectory under your build directory. .I config_h specifies a C header file where the results of tests will be written, e.g. #define HAVE_STDIO_H, #define HAVE_LIBM, etc. The default is to not write a .B config.h file. You can specify the same .B config.h file in multiple calls to Configure, in which case .B scons will concatenate all results in the specified file. Note that SCons uses its normal dependency checking to decide if it's necessary to rebuild the specified .I config_h file. This means that the file is not necessarily re-built each time scons is run, but is only rebuilt if its contents will have changed and some target that depends on the .I config_h file is being built. .EE A created .B Configure instance has the following associated methods: .TP .RI Configure.Finish( self ) This method should be called after configuration is done. It returns the environment as modified by the configuration checks performed. After this method is called, no further checks can be performed with this configuration context. However, you can create a new .RI Configure context to perform additional checks. Only one context should be active at a time. The following Checks are predefined. (This list will likely grow larger as time goes by and developers contribute new useful tests.) .TP .RI Configure.CheckHeader( self ", " header ", [" include_quotes ", " language ]) Checks if .I header is usable in the specified language. .I header may be a list, in which case the last item in the list is the header file to be checked, and the previous list items are header files whose .B #include lines should precede the header line being checked for. The optional argument .I include_quotes must be a two character string, where the first character denotes the opening quote and the second character denotes the closing quote. By default, both characters are " (double quote). The optional argument .I language should be either .B C or .B C++ and selects the compiler to be used for the check. Returns 1 on success and 0 on failure. .TP .RI Configure.CheckCHeader( self ", " header ", [" include_quotes ]) This is a wrapper around .B Configure.CheckHeader which checks if .I header is usable in the C language. .I header may be a list, in which case the last item in the list is the header file to be checked, and the previous list items are header files whose .B #include lines should precede the header line being checked for. The optional argument .I include_quotes must be a two character string, where the first character denotes the opening quote and the second character denotes the closing quote (both default to \N'34'). Returns 1 on success and 0 on failure. .TP .RI Configure.CheckCXXHeader( self ", " header ", [" include_quotes ]) This is a wrapper around .B Configure.CheckHeader which checks if .I header is usable in the C++ language. .I header may be a list, in which case the last item in the list is the header file to be checked, and the previous list items are header files whose .B #include lines should precede the header line being checked for. The optional argument .I include_quotes must be a two character string, where the first character denotes the opening quote and the second character denotes the closing quote (both default to \N'34'). Returns 1 on success and 0 on failure. .TP .RI Configure.CheckFunc( self ", " function_name ", [" header ", " language ]) Checks if the specified C or C++ function is available. .I function_name is the name of the function to check for. The optional .I header argument is a string that will be placed at the top of the test file that will be compiled to check if the function exists; the default is: .ES #ifdef __cplusplus extern "C" #endif char function_name(); .EE The optional .I language argument should be .B C or .B C++ and selects the compiler to be used for the check; the default is "C". .TP .RI Configure.CheckLib( self ", [" library ", " symbol ", " header ", " language ", " autoadd=1 ]) Checks if .I library provides .IR symbol . If the value of .I autoadd is 1 and the library provides the specified .IR symbol , appends the library to the LIBS construction environment variable. .I library may also be None (the default), in which case .I symbol is checked with the current LIBS variable, or a list of library names, in which case each library in the list will be checked for .IR symbol . If .I symbol is not set or is .BR None , then .BR Configure.CheckLib () just checks if you can link against the specified .IR library . The optional .I language argument should be .B C or .B C++ and selects the compiler to be used for the check; the default is "C". The default value for .I autoadd is 1. This method returns 1 on success and 0 on error. .TP .RI Configure.CheckLibWithHeader( self ", " library ", " header ", " language ", [" call ", " autoadd ]) In contrast to the .RI Configure.CheckLib call, this call provides a more sophisticated way to check against libraries. Again, .I library specifies the library or a list of libraries to check. .I header specifies a header to check for. .I header may be a list, in which case the last item in the list is the header file to be checked, and the previous list items are header files whose .B #include lines should precede the header line being checked for. .I language may be one of 'C','c','CXX','cxx','C++' and 'c++'. .I call can be any valid expression (with a trailing ';'). If .I call is not set, the default simply checks that you can link against the specified .IR library . .I autoadd specifies whether to add the library to the environment (only if the check succeeds). This method returns 1 on success and 0 on error. .TP .RI Configure.CheckType( self ", " type_name ", [" includes ", " language ]) Checks for the existence of a type defined by .BR typedef . .I type_name specifies the typedef name to check for. .I includes is a string containing one or more .B #include lines that will be inserted into the program that will be run to test for the existence of the type. The optional .I language argument should be .B C or .B C++ and selects the compiler to be used for the check; the default is "C". .EE Example of a typical Configure usage: .ES env = Environment() conf = Configure( env ) if not conf.CheckCHeader( 'math.h' ): print 'We really need math.h!' Exit(1) if conf.CheckLibWithHeader( 'qt', 'qapp.h', 'c++', 'QApplication qapp(0,0);' ): # do stuff for qt - usage, e.g. conf.env.Append( CPPFLAGS = '-DWITH_QT' ) env = conf.Finish() .EE .EE You can define your own custom checks. in addition to the predefined checks. These are passed in a dictionary to the Configure function. This dictionary maps the names of the checks to user defined Python callables (either Python functions or class instances implementing the .I __call__ method). The first argument of the call is always a .I CheckContext instance followed by the arguments, which must be supplied by the user of the check. These CheckContext instances define the following methods: .TP .RI CheckContext.Message( self ", " text ) Usually called before the check is started. .I text will be displayed to the user, e.g. 'Checking for library X...' .TP .RI CheckContext.Result( self, ", " res ) Usually called after the check is done. .I res can be either an integer or a string. In the former case, 'ok' (res != 0) or 'failed' (res == 0) is displayed to the user, in the latter case the given string is displayed. .TP .RI CheckContext.TryCompile( self ", " text ", " extension ) Checks if a file with the specified .I extension (e.g. '.c') containing .I text can be compiled using the environment's .B Object builder. Returns 1 on success and 0 on failure. .TP .RI CheckContext.TryLink( self ", " text ", " extension ) Checks, if a file with the specified .I extension (e.g. '.c') containing .I text can be compiled using the environment's .B Program builder. Returns 1 on success and 0 on failure. .TP .RI CheckContext.TryRun( self ", " text ", " extension ) Checks, if a file with the specified .I extension (e.g. '.c') containing .I text can be compiled using the environment's .B Program builder. On success, the program is run. If the program executes successfully (that is, its return status is 0), a tuple .I (1, outputStr) is returned, where .I outputStr is the standard output of the program. If the program fails execution (its return status is non-zero), then (0, '') is returned. .TP .RI CheckContext.TryAction( self ", " action ", [" text ", " extension ]) Checks if the specified .I action with an optional source file (contents .I text , extension .I extension = '' ) can be executed. .I action may be anything which can be converted to a .B scons .RI Action. On success, .I (1, outputStr) is returned, where .I outputStr is the content of the target file. On failure .I (0, '') is returned. .TP .RI CheckContext.TryBuild( self ", " builder ", [" text ", " extension ]) Low level implementation for testing specific builds; the methods above are based on this method. Given the Builder instance .I builder and the optional .I text of a source file with optional .IR extension , this method returns 1 on success and 0 on failure. In addition, .I self.lastTarget is set to the build target node, if the build was successful. .EE Example for implementing and using custom tests: .ES def CheckQt(context, qtdir): context.Message( 'Checking for qt ...' ) lastLIBS = context.env['LIBS'] lastLIBPATH = context.env['LIBPATH'] lastCPPPATH= context.env['CPPPATH'] context.env.Append(LIBS = 'qt', LIBPATH = qtdir + '/lib', CPPPATH = qtdir + '/include' ) ret = context.TryLink(""" #include int main(int argc, char **argv) { QApplication qapp(argc, argv); return 0; } """) if not ret: context.env.Replace(LIBS = lastLIBS, LIBPATH=lastLIBPATH, CPPPATH=lastCPPPATH) context.Result( ret ) return ret env = Environment() conf = Configure( env, custom_tests = { 'CheckQt' : CheckQt } ) if not conf.CheckQt('/usr/lib/qt'): print 'We really need qt!' Exit(1) env = conf.Finish() .EE .SS Construction Variable Options Often when building software, various options need to be specified at build time that are not known when the SConstruct/SConscript files are written. For example, libraries needed for the build may be in non-standard locations, or site-specific compiler options may need to be passed to the compiler. .B scons provides a mechanism for overridding construction variables from the command line or a text-based SConscript file through an Options object. To create an Options object, call the Options() function: .TP .RI Options([ files "], [" args ]) This creates an Options object that will read construction variables from the file or list of filenames specified in .IR files . If no files are specified, or the .I files argument is .BR None , then no files will be read. The optional argument .I args is a dictionary of values that will override anything read from the specified files; it is primarily intended to be passed the .B ARGUMENTS dictionary that holds variables specified on the command line. Example: .ES opts = Options('custom.py') opts = Options('overrides.py', ARGUMENTS) opts = Options(None, {FOO:'expansion', BAR:7}) .EE Options objects have the following methods: .TP .RI Add( key ", [" help ", " default ", " validator ", " converter ]) This adds a customizable construction variable to the Options object. .I key is the name of the variable. .I help is the help text for the variable. .I default is the default value of the variable; if the default value is .B None and there is no explicit value specified, the construction variable will .I not be added to the construction environment. .I validator is called to validate the value of the variable, and should take three arguments: key, value, and environment. The recommended way to handle an invalid value is to raise an exception (see example below). .I converter is called to convert the value before putting it in the environment, and should take a single argument: value. The .I converter must return a value, which will be converted into a string before being validated by the .I validator (if any) and then added to the environment. Examples: .ES opts.Add('CC', 'The C compiler') def validate_color(key, val, env): if not val in ['red', 'blue', 'yellow']: raise "Invalid color value '%s'" % val opts.Add('COLOR', validator=valid_color) .EE .TP .RI AddOptions( list ) A wrapper script that adds multiple customizable construction variables to an Options object. .I list is a list of tuple or list objects that contain the arguments for an individual call to the .B Add method. .ES opt.AddOptions( ('debug', '', 0), ('CC', 'The C compiler'), ('VALIDATE', 'An option for testing validation', 'notset', validator, None), ) .EE .TP .RI Update( env ", [" args ]) This updates a construction environment .I env with the customized construction variables. Normally this method is not called directly, but is called indirectly by passing the Options object to the Environment() function: .ES env = Environment(options=opts) .EE .IP The text file(s) that were specified when the Options object was created are executed as Python scripts, and the values of (global) Python variables set in the file are added to the construction environment. Example: .ES CC = 'my_cc' .EE .TP .RI Save( filename ", " env ) This saves the currently set options into a script file named .I filename that can be used on the next invocation to automatically load the current settings. This method combined with the Options method can be used to support caching of options between runs. .ES env = Environment() opts = Options(['options.cache', 'custom.py']) opts.Add(...) opts.Update(env) opts.Save('options.cache', env) .EE .TP .RI GenerateHelpText( env ", [" sort ]) This generates help text documenting the customizable construction variables suitable to passing in to the Help() function. .I env is the construction environment that will be used to get the actual values of customizable variables. Calling with an optional .I sort function will cause the output to be sorted by the specified argument. The specific .I sort function should take two arguments and return -1, 0 or 1 (like the standard Python .I cmp function). .ES Help(opts.GenerateHelpText(env)) Help(opts.GenerateHelpText(env, sort=cmp)) .EE .TP .RI FormatOptionHelpText( env ", " opt ", " help ", " default ", " actual ) This method returns a formatted string containing the printable help text for one option. It is normally not called directly, but is called by the .IR GenerateHelpText () method to create the returned help text. It may be overridden with your own function that takes the arguments specified above and returns a string of help text formatted to your liking. Note that the .IR GenerateHelpText () will not put any blank lines or extra characters in between the entries, so you must add those characters to the returned string if you want the entries separated. .ES def my_format(env, opt, help, default, actual): fmt = "\n%s: default=%s actual=%s (%s)\n" return fmt % (opt, default. actual, help) opts.FormatOptionHelpText = my_format .EE To make it more convenient to work with customizable Options, .B scons provides a number of functions that make it easy to set up various types of Options: .TP .RI BoolOption( key ", " help ", " default ) Return a tuple of arguments to set up a Boolean option. The option will use the specified name .IR key , have a default value of .IR default , and display the specified .I help text. The option will interpret the values .BR y , .BR yes , .BR t , .BR true , .BR 1 , .B on and .B all as true, and the values .BR n , .BR no , .BR f , .BR false , .BR 0 , .B off and .B none as false. .TP .RI EnumOption( key ", " help ", " default ", " allowed_values ", [" map ", " ignorecase ]) Return a tuple of arguments to set up an option whose value may be one of a specified list of legal enumerated values. The option will use the specified name .IR key , have a default value of .IR default , and display the specified .I help text. The option will only support those values in the .I allowed_values list. The optional .I map argument is a dictionary that can be used to convert input values into specific legal values in the .I allowed_values list. If the value of .I ignore_case is .B 0 (the default), then the values are case-sensitive. If the value of .I ignore_case is .BR 1 , then values will be matched case-insensitive. If the value of .I ignore_case is .BR 1 , then values will be matched case-insensitive, and all input values will be converted to lower case. .TP .RI ListOption( key ", " help ", " default ", " names ", [", map ]) Return a tuple of arguments to set up an option whose value may be one or more of a specified list of legal enumerated values. The option will use the specified name .IR key , have a default value of .IR default , and display the specified .I help text. The option will only support the values .BR all , .BR none , or the values in the .I names list. More than one value may be specified, with all values separated by commas. The default may be a string of comma-separated default values, or a list of the default values. The optional .I map argument is a dictionary that can be used to convert input values into specific legal values in the .I names list. .TP .RI PackageOption( key ", " help ", " default ) Return a tuple of arguments to set up an option whose value is a path name of a package that may be enabled, disabled or given an explicit path name. The option will use the specified name .IR key , have a default value of .IR default , and display the specified .I help text. The option will support the values .BR yes , .BR true , .BR on , .BR enable or .BR search , in which case the specified .I default will be used, or the option may be set to an arbitrary string (typically the path name to a package that is being enabled). The option will also support the values .BR no , .BR false , .BR off or .BR disable to disable use of the specified option. .TP .RI PathOption( key ", " help ", " default ", [" validator ]) Return a tuple of arguments to set up an option whose value is expected to be a path name. The option will use the specified name .IR key , have a default value of .IR default , and display the specified .I help text. An additional .I validator may be specified that will be called to verify that the specified path is acceptable. SCons supplies the following ready-made validators: .BR PathOption.PathExists (the default), which verifies that the specified path exists; .BR PathOption.PathIsFile , which verifies that the specified path is an existing file; .BR PathOption.PathIsDir , which verifies that the specified path is an existing directory; and .BR PathOption.PathIsDirCreate , which verifies that the specified path is a directory, and will create the specified directory if the path does not exist. You may supply your own .I validator function, which must take three arguments .RI ( key , the name of the options variable to be set; .IR val , the specified value being checked; and .IR env , the construction environment) and should raise an exception if the specified value is not acceptable. .RE These functions make it convenient to create a number of options with consistent behavior in a single call to the .B AddOptions method: .ES opts.AddOptions( BoolOption('warnings', 'compilation with -Wall and similiar', 1), EnumOption('debug', 'debug output and symbols', 'no' allowed_values=('yes', 'no', 'full'), map={}, ignorecase=0), # case sensitive ListOption('shared', 'libraries to build as shared libraries', 'all', names = list_of_libs), PackageOption('x11', 'use X11 installed here (yes = search some places)', 'yes'), PathOption('qtdir', 'where the root of Qt is installed', qtdir), PathOption('foopath', 'where the foo library is installed', foopath, PathOption.PathIsDir), ) .EE .SS File and Directory Nodes The .IR File () and .IR Dir () functions return .I File and .I Dir Nodes, respectively. python objects, respectively. Those objects have several user-visible attributes and methods that are often useful: .IP path The build path of the given file or directory. This path is relative to the top-level directory (where the .B SConstruct file is found). The build path is the same as the source path if .I build_dir is not being used. .IP abspath The absolute build path of the given file or directory. .IP srcnode() The .IR srcnode () method returns another .I File or .I Dir object representing the .I source path of the given .I File or .IR Dir . The .ES # Get the current build dir's path, relative to top. Dir('.').path # Current dir's absolute path Dir('.').abspath # Next line is always '.', because it is the top dir's path relative to itself. Dir('#.').path File('foo.c').srcnode().path # source path of the given source file. # Builders also return File objects: foo = env.Program('foo.c') print "foo will be built in %s"%foo.path .EE .SH EXTENDING SCONS .SS Builder Objects .B scons can be extended to build different types of targets by adding new Builder objects to a construction environment. .IR "In general" , you should only need to add a new Builder object when you want to build a new type of file or other external target. If you just want to invoke a different compiler or other tool to build a Program, Object, Library, or any other type of output file for which .B scons already has an existing Builder, it is generally much easier to use those existing Builders in a construction environment that sets the appropriate construction variables (CC, LINK, etc.). Builder objects are created using the .B Builder function. The .B Builder function accepts the following arguments: .IP action The command line string used to build the target from the source. .B action can also be: a list of strings representing the command to be executed and its arguments (suitable for enclosing white space in an argument), a dictionary mapping source file name suffixes to any combination of command line strings (if the builder should accept multiple source file extensions), a Python function; an Action object (see the next section); or a list of any of the above. An action function takes three arguments: .I source - a list of source nodes, .I target - a list of target nodes, .I env - the construction environment. .IP prefix The prefix that will be prepended to the target file name. This may be specified as a: .RS 10 .HP 6 * .IR string , .HP 6 * .I callable object - a function or other callable that takes two arguments (a construction environment and a list of sources) and returns a prefix, .HP 6 * .I dictionary - specifies a mapping from a specific source suffix (of the first source specified) to a corresponding target prefix. Both the source suffix and target prefix specifications may use environment variable substitution, and the target prefix (the 'value' entries in the dictionary) may also be a callable object. The default target prefix may be indicated by a dictionary entry with a key value of None. .RE .P .ES b = Builder("build_it < $SOURCE > $TARGET" prefix = "file-") def gen_prefix(env, sources): return "file-" + env['PLATFORM'] + '-' b = Builder("build_it < $SOURCE > $TARGET", prefix = gen_prefix) b = Builder("build_it < $SOURCE > $TARGET", suffix = { None: "file-", "$SRC_SFX_A": gen_prefix }) .EE .IP suffix The suffix that will be appended to the target file name. This may be specified in the same manner as the prefix above. If the suffix is a string, then .B scons will append a '.' to the beginning of the suffix if it's not already there. The string returned by callable object (or obtained from the dictionary) is untouched and must append its own '.' to the beginning if one is desired. .ES b = Builder("build_it < $SOURCE > $TARGET" suffix = "-file") def gen_suffix(env, sources): return "." + env['PLATFORM'] + "-file" b = Builder("build_it < $SOURCE > $TARGET", suffix = gen_suffix) b = Builder("build_it < $SOURCE > $TARGET", suffix = { None: ".sfx1", "$SRC_SFX_A": gen_suffix }) .EE .IP src_suffix The expected source file name suffix. This may be a string or a list of strings. .IP target_scanner A Scanner object that will be invoked to find implicit dependencies for this target file. This keyword argument should be used for Scanner objects that find implicit dependencies based only on the target file and the construction environment, .I not for implicit (See the section "Scanner Objects," below, for information about creating Scanner objects.) .IP source_scanner A Scanner object that will be invoked to find implicit dependences in any source files used to build this target file. This is where you would specify a scanner to find things like .B #include lines in source files. The pre-built .B DirScanner Scanner object may be used to indicate that this Builder should scan directory trees for on-disk changes to files that .B scons does not know about from other Builder or function calls. (See the section "Scanner Objects," below, for information about creating your own Scanner objects.) .IP target_factory A factory function that the Builder will use to turn any targets specified as strings into SCons Nodes. By default, SCons assumes that all targets are files. Other useful target_factory values include .BR Dir , for when a Builder creates a directory target, and .BR Entry , for when a Builder can create either a file or directory target. Example: .ES MakeDirectoryBuilder = Builder(action=my_mkdir, target_factory=Dir) env = Environment() env.Append(BUILDERS = {'MakeDirectory':MakeDirectoryBuilder}) env.MakeDirectory('new_directory', []) .EE Note that the call to the MakeDirectory Builder needs to specify an empty source list to make the string represent the builder's target; without that, it would assume the argument is the source, and would try to deduce the target name from it, which in the absence of an automatically-added prefix or suffix would lead to a matching target and source name and a circular dependency. .IP source_factory A factory function that the Builder will use to turn any sources specified as strings into SCons Nodes. By default, SCons assumes that all source are files. Other useful source_factory values include .BR Dir , for when a Builder uses a directory as a source, and .BR Entry , for when a Builder can use files or directories (or both) as sources. Example: .ES CollectBuilder = Builder(action=my_mkdir, source_factory=Entry) env = Environment() env.Append(BUILDERS = {'Collect':CollectBuilder}) env.Collect('archive', ['directory_name', 'file_name']) .EE .IP emitter A function or list of functions to manipulate the target and source lists before dependencies are established and the target(s) are actually built. .B emitter can also be a string containing a construction variable to expand to an emitter function or list of functions, or a dictionary mapping source file suffixes to emitter functions. (Only the suffix of the first source file is used to select the actual emitter function from an emitter dictionary.) An emitter function takes three arguments: .I source - a list of source nodes, .I target - a list of target nodes, .I env - the construction environment. An emitter must return a tuple containing two lists, the list of targets to be built by this builder, and the list of sources for this builder. Example: .ES def e(target, source, env): return (target + ['foo.foo'], source + ['foo.src']) # Simple association of an emitter function with a Builder. b = Builder("my_build < $TARGET > $SOURCE", emitter = e) def e2(target, source, env): return (target + ['bar.foo'], source + ['bar.src']) # Simple association of a list of emitter functions with a Builder. b = Builder("my_build < $TARGET > $SOURCE", emitter = [e, e2]) # Calling an emitter function through a construction variable. env = Environment(MY_EMITTER = e) b = Builder("my_build < $TARGET > $SOURCE", emitter = '$MY_EMITTER') # Calling a list of emitter functions through a construction variable. env = Environment(EMITTER_LIST = [e, e2]) b = Builder("my_build < $TARGET > $SOURCE", emitter = '$EMITTER_LIST') # Associating multiple emitters with different file # suffixes using a dictionary. def e_suf1(target, source, env): return (target + ['another_target_file'], source) def e_suf2(target, source, env): return (target, source + ['another_source_file']) b = Builder("my_build < $TARGET > $SOURCE", emitter = {'.suf1' : e_suf1, '.suf2' : e_suf2}) .EE .IP multi Specifies whether this builder is allowed to be called multiple times for the same target file(s). The default is 0, which means the builder can not be called multiple times for the same target file(s). Calling a builder multiple times for the same target simply adds additional source files to the target; it is not allowed to change the environment associated with the target, specify addition environment overrides, or associate a different builder with the target. .IP env A construction environment that can be used to fetch source code using this Builder. (Note that this environment is .I not used for normal builds of normal target files, which use the environment that was used to call the Builder for the target file.) .IP generator A function that returns a list of actions that will be executed to build the target(s) from the source(s). The returned action(s) may be an Action object, or anything that can be converted into an Action object (see the next section). The generator function takes four arguments: .I source - a list of source nodes, .I target - a list of target nodes, .I env - the construction environment, .I for_signature - a Boolean value that specifies whether the generator is being called for generating a build signature (as opposed to actually executing the command). Example: .ES def g(source, target, env, for_signature): return [["gcc", "-c", "-o"] + target + source] b = Builder(generator=g) .EE .IP The .I generator and .I action arguments must not both be used for the same Builder. .IP src_builder Specifies a builder to use when a source file name suffix does not match any of the suffixes of the builder. Using this argument produces a multi-stage builder. .IP single_source Specifies that this builder expects exactly one source file per call. Giving more than one source files without target files results in implicitely calling the builder multiple times (once for each source given). Giving multiple source files together with target files results in a UserError exception. .RE .IP The .I generator and .I action arguments must not both be used for the same Builder. .IP source_ext_match When the specified .I action argument is a dictionary, the default behavior when a builder is passed multiple source files is to make sure that the extensions of all the source files match. If it is legal for this builder to be called with a list of source files with different extensions, this check can be suppressed by setting .B source_ext_match to .B None or some other non-true value. When .B source_ext_match is disable, .B scons will use the suffix of the first specified source file to select the appropriate action from the .I action dictionary. In the following example, the setting of .B source_ext_match prevents .B scons from exiting with an error due to the mismatched suffixes of .B foo.in and .BR foo.extra . .ES b = Builder(action={'.in' : 'build $SOURCES > $TARGET'}, source_ext_match = None) env = Environment(BUILDERS = {'MyBuild':b}) env.MyBuild('foo.out', ['foo.in', 'foo.extra']) .EE .IP env A construction environment that can be used to fetch source code using this Builder. (Note that this environment is .I not used for normal builds of normal target files, which use the environment that was used to call the Builder for the target file.) .ES b = Builder(action="build < $SOURCE > $TARGET") env = Environment(BUILDERS = {'MyBuild' : b}) env.MyBuild('foo.out', 'foo.in', my_arg = 'xyzzy') .EE .IP chdir A directory from which scons will execute the action(s) specified for this Builder. If the .B chdir argument is a string or a directory Node, scons will change to the specified directory. If the .B chdir is not a string or Node and is non-zero, then scons will change to the target file's directory. Note that scons will .I not automatically modify its expansion of construction variables like .B $TARGET and .B $SOURCE when using the chdir keyword argument--that is, the expanded file names will still be relative to the top-level SConstruct directory, and consequently incorrect relative to the chdir directory. Builders created using chdir keyword argument, will need to use construction variable expansions like .B ${TARGET.file} and .B ${SOURCE.file} to use just the filename portion of the targets and source. .ES b = Builder(action="build < ${SOURCE.file} > ${TARGET.file}", chdir=1) env = Environment(BUILDERS = {'MyBuild' : b}) env.MyBuild('sub/dir/foo.out', 'sub/dir/foo.in') .EE .B WARNING: Python only keeps one current directory location for all of the threads. This means that use of the .B chdir argument will .I not work with the SCons .B -j option, because individual worker threads spawned by SCons interfere with each other when they start changing directory. .RE Any additional keyword arguments supplied when a Builder object is created (that is, when the Builder() function is called) will be set in the executing construction environment when the Builder object is called. The canonical example here would be to set a construction variable to the repository of a source code system. Any additional keyword arguments supplied when a Builder .I object is called will only be associated with the target created by that particular Builder call (and any other files built as a result of the call). These extra keyword arguments are passed to the following functions: command generator functions, function Actions, and emitter functions. .SS Action Objects The .BR Builder() function will turn its .B action keyword argument into an appropriate internal Action object. You can also explicity create Action objects using the .BR Action () global function, which can then be passed to the .BR Builder () function. This can be used to configure an Action object more flexibly, or it may simply be more efficient than letting each separate Builder object create a separate Action when multiple Builder objects need to do the same thing. The .BR Action () global function returns an appropriate object for the action represented by the type of the first argument: .IP Action If the first argument is already an Action object, the object is simply returned. .IP String If the first argument is a string, a command-line Action is returned. Note that the command line string may be preceded by an .B @ (at-sign) to suppress printing of the specified command line, or by a .B \- (hyphen) to ignore the exit status from the specified command. Examples: .ES Action('$CC -c -o $TARGET $SOURCES') # Doesn't print the line being executed. Action('@build $TARGET $SOURCES') # Ignores Action('-build $TARGET $SOURCES') .EE .\" XXX From Gary Ruben, 23 April 2002: .\" What would be useful is a discussion of how you execute command .\" shell commands ie. what is the process used to spawn the shell, pass .\" environment variables to it etc., whether there is one shell per .\" environment or one per command etc. It might help to look at the Gnu .\" make documentation to see what they think is important to discuss about .\" a build system. I'm sure you can do a better job of organising the .\" documentation than they have :-) .IP List If the first argument is a list, then a list of Action objects is returned. An Action object is created as necessary for each element in the list. If an element .I within the list is itself a list, the internal list is the command and arguments to be executed via the command line. This allows white space to be enclosed in an argument by defining a command in a list within a list: .ES Action([['cc', '-c', '-DWHITE SPACE', '-o', '$TARGET', '$SOURCES']]) .EE .IP Function If the first argument is a Python function, a function Action is returned. The Python function takes three keyword arguments, .B target (a Node object representing the target file), .B source (a Node object representing the source file) and .B env (the construction environment used for building the target file). The .B target and .B source arguments may be lists of Node objects if there is more than one target file or source file. The actual target and source file name(s) may be retrieved from their Node objects via the built-in Python str() function: .ES target_file_name = str(target) source_file_names = map(lambda x: str(x), source) .EE .IP The function should return .B 0 or .B None to indicate a successful build of the target file(s). The function may raise an exception or return a non-zero exit status to indicate an unsuccessful build. .ES def build_it(target = None, source = None, env = None): # build the target from the source return 0 a = Action(build_it) .EE If the action argument is not one of the above, None is returned. .PP The second, optional argument is used to define the output which is printed when the Action is actually performed. In the absence of this parameter, or if it's an empty string, a default output depending on the type of the action is used. For example, a command-line action will print the executed command. The argument is either a python function or a string. In the first case, it's a function that returns a string to be printed to describe the action being executed. Like a function to build a file, this function takes three arguments: .B target (a Node object representing the target file), .B source (a Node object representing the source file) and .BR env (a construction environment). The .B target and .B source arguments may be lists of Node objects if there is more than one target file or source file. In the second case, you provide the string itself. The string typically contains variables, notably $TARGET(S) and $SOURCE(S), or consists of just a single variable, which is optionally defined somewhere else. SCons itself heavily uses the latter variant. Examples: .ES def build_it(target, source, env): # build the target from the source return 0 def string_it(target, source, env): return "building '%s' from '%s'" % (target[0], source[0]) # Use a positional argument. f = Action(build_it, string_it) s = Action(build_it, "building '$TARGET' from '$SOURCE'") # Alternatively, use a keyword argument. f = Action(build_it, strfunction=string_it) s = Action(build_it, cmdstr="building '$TARGET' from '$SOURCE'") # You can provide a configurable variable. l = Action(build_it, '$STRINGIT') .EE The third, also optional argument is a list of construction variables whose values will be included in the signature of the Action when deciding whether a target should be rebuilt because the action changed. This is necessary whenever you want a target to be rebuilt when a specific construction variable changes, because the underlying Python code for a function will not change when the value of the construction variable does. .ES def build_it(target, source, env): # build the target from the 'XXX' construction variable open(target[0], 'w').write(env['XXX']) return 0 # Use positional arguments. a = Action(build_it, '$STRINGIT', ['XXX']) # Alternatively, use a keyword argument. a = Action(build_it, varlist=['XXX']) .EE The .BR Action () global function also takes a .B chdir keyword argument which specifies that scons will execute the action after changing to the specified directory. If the chdir argument is a string or a directory Node, scons will change to the specified directory. If the chdir argument is not a string or Node and is non-zero, then scons will change to the target file's directory. Note that scons will .I not automatically modify its expansion of construction variables like .B $TARGET and .B $SOURCE when using the chdir keyword argument--that is, the expanded file names will still be relative to the top-level SConstruct directory, and consequently incorrect relative to the chdir directory. Builders created using chdir keyword argument, will need to use construction variable expansions like .B ${TARGET.file} and .B ${SOURCE.file} to use just the filename portion of the targets and source. .ES a = Action("build < ${SOURCE.file} > ${TARGET.file}", chdir=1) .EE The .BR Action () global function also takes an .B exitstatfunc keyword argument which specifies a function that is passed the exit status (or return value) from the specified action and can return an arbitrary or modified value. This can be used, for example, to specify that an Action object's return value should be ignored and SCons should, therefore, consider that the action always suceeds: .ES def always_succeed(s): # Always return 0, which indicates success. return 0 a = Action("build < ${SOURCE.file} > ${TARGET.file}", exitstatfunc=always_succeed) .EE .SS Miscellaneous Action Functions .B scons supplies a number of functions that arrange for various common file and directory manipulations to be performed. These are similar in concept to "tasks" in the Ant build tool, although the implementation is slightly different. These functions do not actually perform the specified action at the time the function is called, but instead return an Action object that can be executed at the appropriate time. (In Object-Oriented terminology, these are actually Action .I Factory functions that return Action objects.) In practice, there are two natural ways that these Action Functions are intended to be used. First, if you need to perform the action at the time the SConscript file is being read, you can use the .B Execute global function to do so: .ES Execute(Touch('file')) .EE Second, you can use these functions to supply Actions in a list for use by the .B Command method. This can allow you to perform more complicated sequences of file manipulation without relying on platform-specific external commands: that .ES env = Environment(TMPBUILD = '/tmp/builddir') env.Command('foo.out', 'foo.in', [Mkdir('$TMPBUILD'), Copy('$TMPBUILD', '${SOURCE.dir}'), "cd $TMPBUILD && make", Delete('$TMPBUILD')]) .EE .TP .RI Chmod( dest ", " mode ) Returns an Action object that changes the permissions on the specified .I dest file or directory to the specified .IR mode . Examples: .ES Execute(Chmod('file', 0755)) env.Command('foo.out', 'foo.in', [Copy('$TARGET', '$SOURCE'), Chmod('$TARGET', 0755)]) .EE .TP .RI Copy( dest ", " src ) Returns an Action object that will copy the .I src source file or directory to the .I dest destination file or directory. Examples: .ES Execute(Copy('foo.output', 'foo.input')) env.Command('bar.out', 'bar.in', Copy('$TARGET', '$SOURCE')) .EE .TP .RI Delete( entry ", [" must_exist ]) Returns an Action that deletes the specified .IR entry , which may be a file or a directory tree. If a directory is specified, the entire directory tree will be removed. If the .I must_exist flag is set, then a Python error will be thrown if the specified entry does not exist; the default is .BR must_exist=0 , that is, the Action will silently do nothing if the entry does not exist. Examples: .ES Execute(Delete('/tmp/buildroot')) env.Command('foo.out', 'foo.in', [Delete('${TARGET.dir}'), MyBuildAction]) Execute(Delete('file_that_must_exist', must_exist=1)) .EE .TP .RI Mkdir( dir ) Returns an Action that creates the specified directory .I dir . Examples: .ES Execute(Mkdir('/tmp/outputdir')) env.Command('foo.out', 'foo.in', [Mkdir('/tmp/builddir', Copy('$SOURCE', '/tmp/builddir') "cd /tmp/builddir && ]) .EE .TP .RI Move( dest ", " src ) Returns an Action that moves the specified .I src file or directory to the specified .I dest file or directory. Examples: .ES Execute(Move('file.destination', 'file.source')) env.Command('output_file', 'input_file', [MyBuildAction, Move('$TARGET', 'file_created_by_MyBuildAction')]) .EE .TP .RI Touch( file ) Returns an Action that updates the modification time on the specified .IR file . Examples: .ES Execute(Touch('file_to_be_touched')) env.Command('marker', 'input_file', [MyBuildAction, Touch('$TARGET')]) .EE .SS Variable Substitution Before executing a command, .B scons performs construction variable interpolation on the strings that make up the command line of builders. Variables are introduced by a .B $ prefix. Besides construction variables, scons provides the following variables for each command execution: .IP TARGET The file name of the target being built, or the file name of the first target if multiple targets are being built. .IP TARGETS The file names of all targets being built. .IP SOURCE The file name of the source of the build command, or the file name of the first source if multiple sources are being built. .IP SOURCES The file names of the sources of the build command. (Note that the above variables are reserved and may not be set in a construction environment.) .LP For example, given the construction variable CC='cc', targets=['foo'], and sources=['foo.c', 'bar.c']: .ES action='$CC -c -o $TARGET $SOURCES' .EE would produce the command line: .ES cc -c -o foo foo.c bar.c .EE Variable names may be surrounded by curly braces ({}) to separate the name from the trailing characters. Within the curly braces, a variable name may have a Python slice subscript appended to select one or more items from a list. In the previous example, the string: .ES ${SOURCES[1]} .EE would produce: .ES bar.c .EE Additionally, a variable name may have the following special modifiers appended within the enclosing curly braces to modify the interpolated string: .IP base The base path of the file name, including the directory path but excluding any suffix. .IP dir The name of the directory in which the file exists. .IP file The file name, minus any directory portion. .IP filebase Just the basename of the file, minus any suffix and minus the directory. .IP suffix Just the file suffix. .IP abspath The absolute path name of the file. .IP posix The POSIX form of the path, with directories separated by .B / (forward slashes) not backslashes. This is sometimes necessary on Windows systems when a path references a file on other (POSIX) systems. .IP srcpath The directory and file name to the source file linked to this file through BuildDir. If this file isn't linked, it just returns the directory and filename unchanged. .IP srcdir The directory containing the source file linked to this file through BuildDir. If this file isn't linked, it just returns the directory part of the filename. .IP rsrcpath The directory and file name to the source file linked to this file through BuildDir. If the file does not exist locally but exists in a Repository, the path in the Repository is returned. If this file isn't linked, it just returns the directory and filename unchanged. .IP rsrcdir The Repository directory containing the source file linked to this file through BuildDir. If this file isn't linked, it just returns the directory part of the filename. .LP For example, the specified target will expand as follows for the corresponding modifiers: .ES $TARGET => sub/dir/file.x ${TARGET.base} => sub/dir/file ${TARGET.dir} => sub/dir ${TARGET.file} => file.x ${TARGET.filebase} => file ${TARGET.suffix} => .x ${TARGET.abspath} => /top/dir/sub/dir/file.x SConscript('src/SConscript', build_dir='sub/dir') $SOURCE => sub/dir/file.x ${SOURCE.srcpath} => src/file.x ${SOURCE.srcdir} => src Repository('/usr/repository') $SOURCE => sub/dir/file.x ${SOURCE.rsrcpath} => /usr/repository/src/file.x ${SOURCE.rsrcdir} => /usr/repository/src .EE Lastly, a variable name may be a callable Python function associated with a construction variable in the environment. The function should take four arguments: .I target - a list of target nodes, .I source - a list of source nodes, .I env - the construction environment, .I for_signature - a Boolean value that specifies whether the function is being called for generating a build signature. SCons will insert whatever the called function returns into the expanded string: .ES def foo(target, source, env, for_signature): return "bar" # Will expand $BAR to "bar baz" env=Environment(FOO=foo, BAR="$FOO baz") .EE You can use this feature to pass arguments to a Python function by creating a callable class that stores one or more arguments in an object, and then uses them when the .B __call__() method is called. Note that in this case, the entire variable expansion must be enclosed by curly braces so that the arguments will be associated with the instantiation of the class: .ES class foo: def __init__(self, arg): self.arg = arg def __call__(self, target, source, env, for_signature): return arg + " bar" # Will expand $BAR to "my argument bar baz" env=Environment(FOO=foo, BAR="${FOO('my argument')} baz") .EE .LP The special pseudo-variables .B "$(" and .B "$)" may be used to surround parts of a command line that may change .I without causing a rebuild--that is, which are not included in the signature of target files built with this command. All text between .B "$(" and .B "$)" will be removed from the command line before it is added to file signatures, and the .B "$(" and .B "$)" will be removed before the command is executed. For example, the command line: .ES echo Last build occurred $( $TODAY $). > $TARGET .EE .LP would execute the command: .ES echo Last build occurred $TODAY. > $TARGET .EE .LP but the command signature added to any target files would be: .ES echo Last build occurred . > $TARGET .EE SCons uses the following rules when converting construction variables into command lines: .IP String When the value is a string it is interpreted as a space delimited list of command line arguments. .IP List When the value is a list it is interpreted as a list of command line arguments. Each element of the list is converted to a string. .IP Other Anything that is not a list or string is converted to a string and interpreted as a single command line argument. .IP Newline Newline characters (\\n) delimit lines. The newline parsing is done after all other parsing, so it is not possible for arguments (e.g. file names) to contain embedded newline characters. This limitation will likely go away in a future version of SCons. .SS Scanner Objects You can use the .B Scanner function to define objects to scan new file types for implicit dependencies. Scanner accepts the following arguments: .IP function A Python function that will process the Node (file) and return a list of strings (file names) representing the implicit dependencies found in the contents. The function takes three or four arguments: def scanner_function(node, env, path): def scanner_function(node, env, path, arg): The .B node argument is the internal SCons node representing the file. Use .B str(node) to fetch the name of the file, and .B node.get_contents() to fetch contents of the file. Note that the file is .I not guaranteed to exist before the scanner is called, so the scanner function should check that if there's any chance that the scanned file might not exist (for example, if it's built from other files). The .B env argument is the construction environment for the scan. Fetch values from it using the .B env.Dictionary() method. The .B path argument is a tuple (or list) of directories that can be searched for files. This will usually be the tuple returned by the .B path_function argument (see below). The .B arg argument is the argument supplied when the scanner was created, if any. .IP name The name of the Scanner. This is mainly used to identify the Scanner internally. .IP argument An optional argument that, if specified, will be passed to the scanner function (described above) and the path function (specified below). .IP skeys An optional list that can be used to determine which scanner should be used for a given Node. In the usual case of scanning for file names, this argument will be a list of suffixes for the different file types that this Scanner knows how to scan. If the argument is a string, then it will be expanded into a list by the current environment. .IP path_function A Python function that takes four or five arguments: a construction environment, a Node for the directory containing the SConscript file in which the first target was defined, a list of target nodes, a list of source nodes, and an optional argument supplied when the scanner was created. The .B path_function returns a tuple of directories that can be searched for files to be returned by this Scanner object. .IP node_class The class of Node that should be returned by this Scanner object. Any strings or other objects returned by the scanner function that are not of this class will be run through the .B node_factory function. .IP node_factory A Python function that will take a string or other object and turn it into the appropriate class of Node to be returned by this Scanner object. .IP scan_check An optional Python function that takes two arguments, a Node (file) and a construction environment, and returns whether the Node should, in fact, be scanned for dependencies. This check can be used to eliminate unnecessary calls to the scanner function when, for example, the underlying file represented by a Node does not yet exist. .IP recursive An optional flag that specifies whether this scanner should be re-invoked on the dependency files returned by the scanner. When this flag is not set, the Node subsystem will only invoke the scanner on the file being scanned, and not (for example) also on the files specified by the #include lines in the file being scanned. .I recursive may be a callable function, in which case it will be called with a list of Nodes found and should return a list of Nodes that should be scanned recursively; this can be used to select a specific subset of Nodes for additional scanning. Note that .B scons has a global .B SourceFileScanner object that is used by the .BR Object (), .BR SharedObject (), and .BR StaticObject () builders to decide which scanner should be used for different file extensions. You can using the .BR SourceFileScanner.add_scanner () method to add your own Scanner object to the .B scons infrastructure that builds target programs or libraries from a list of source files of different types: .ES def xyz_scan(node, env, path): contents = node.get_contents() # Scan the contents and return the included files. XYZScanner = Scanner(xyz_scan) SourceFileScanner.add_scanner('.xyx', XYZScanner) env.Program('my_prog', ['file1.c', 'file2.f', 'file3.xyz']) .EE .SH SYSTEM-SPECIFIC BEHAVIOR SCons and its configuration files are very portable, due largely to its implementation in Python. There are, however, a few portability issues waiting to trap the unwary. .SS .C file suffix SCons handles the upper-case .B .C file suffix differently, depending on the capabilities of the underlying system. On a case-sensitive system such as Linux or UNIX, SCons treats a file with a .B .C suffix as a C++ source file. On a case-insensitive system such as Windows, SCons treats a file with a .B .C suffix as a C source file. .SS .F file suffix SCons handles the upper-case .B .F file suffix differently, depending on the capabilities of the underlying system. On a case-sensitive system such as Linux or UNIX, SCons treats a file with a .B .F suffix as a Fortran source file that is to be first run through the standard C preprocessor. On a case-insensitive system such as Windows, SCons treats a file with a .B .F suffix as a Fortran source file that should .I not be run through the C preprocessor. .SS Windows: Cygwin Tools and Cygwin Python vs. Windows Pythons Cygwin supplies a set of tools and utilities that let users work on a Windows system using a more POSIX-like environment. The Cygwin tools, including Cygwin Python, do this, in part, by sharing an ability to interpret UNIX-like path names. For example, the Cygwin tools will internally translate a Cygwin path name like /cygdrive/c/mydir to an equivalent Windows pathname of C:/mydir (equivalent to C:\\mydir). Versions of Python that are built for native Windows execution, such as the python.org and ActiveState versions, do not have the Cygwin path name semantics. This means that using a native Windows version of Python to build compiled programs using Cygwin tools (such as gcc, bison, and flex) may yield unpredictable results. "Mixing and matching" in this way can be made to work, but it requires careful attention to the use of path names in your SConscript files. In practice, users can sidestep the issue by adopting the following rules: When using gcc, use the Cygwin-supplied Python interpreter to run SCons; when using Microsoft Visual C/C++ (or some other Windows compiler) use the python.org or ActiveState version of Python to run SCons. .SS Windows: scons.bat file On Windows systems, SCons is executed via a wrapper .B scons.bat file. This has (at least) two ramifications: First, Windows command-line users that want to use variable assignment on the command line may have to put double quotes around the assignments: .ES scons "FOO=BAR" "BAZ=BLEH" .EE Second, the Cygwin shell does not recognize this file as being the same as an .B scons command issued at the command-line prompt. You can work around this either by executing .B scons.bat from the Cygwin command line, or by creating a wrapper shell script named .B scons . .SS MinGW The MinGW bin directory must be in your PATH environment variable or the PATH variable under the ENV construction variable for SCons to detect and use the MinGW tools. When running under the native Windows Python interpreter, SCons will prefer the MinGW tools over the Cygwin tools, if they are both installed, regardless of the order of the bin directories in the PATH variable. If you have both MSVC and MinGW installed and you want to use MinGW instead of MSVC, then you must explictly tell SCons to use MinGW by passing .ES tools=['mingw'] .EE to the Environment() function, because SCons will prefer the MSVC tools over the MinGW tools. .SH EXAMPLES To help you get started using SCons, this section contains a brief overview of some common tasks. .SS Basic Compilation From a Single Source File .ES env = Environment() env.Program(target = 'foo', source = 'foo.c') .EE Note: Build the file by specifying the target as an argument ("scons foo" or "scons foo.exe"). or by specifying a dot ("scons ."). .SS Basic Compilation From Multiple Source Files .ES env = Environment() env.Program(target = 'foo', source = Split('f1.c f2.c f3.c')) .EE .SS Setting a Compilation Flag .ES env = Environment(CCFLAGS = '-g') env.Program(target = 'foo', source = 'foo.c') .EE .SS Search The Local Directory For .h Files Note: You do .I not need to set CCFLAGS to specify -I options by hand. SCons will construct the right -I options from CPPPATH. .ES env = Environment(CPPPATH = ['.']) env.Program(target = 'foo', source = 'foo.c') .EE .SS Search Multiple Directories For .h Files .ES env = Environment(CPPPATH = ['include1', 'include2']) env.Program(target = 'foo', source = 'foo.c') .EE .SS Building a Static Library .ES env = Environment() env.StaticLibrary(target = 'foo', source = Split('l1.c l2.c')) env.StaticLibrary(target = 'bar', source = ['l3.c', 'l4.c']) .EE .SS Building a Shared Library .ES env = Environment() env.SharedLibrary(target = 'foo', source = ['l5.c', 'l6.c']) env.SharedLibrary(target = 'bar', source = Split('l7.c l8.c')) .EE .SS Linking a Local Library Into a Program .ES env = Environment(LIBS = 'mylib', LIBPATH = ['.']) env.Library(target = 'mylib', source = Split('l1.c l2.c')) env.Program(target = 'prog', source = ['p1.c', 'p2.c']) .EE .SS Defining Your Own Builder Object Notice that when you invoke the Builder, you can leave off the target file suffix, and SCons will add it automatically. .ES bld = Builder(action = 'pdftex < $SOURCES > $TARGET' suffix = '.pdf', src_suffix = '.tex') env = Environment(BUILDERS = {'PDFBuilder' : bld}) env.PDFBuilder(target = 'foo.pdf', source = 'foo.tex') # The following creates "bar.pdf" from "bar.tex" env.PDFBuilder(target = 'bar', source = 'bar') .EE Note also that the above initialization overwrites the default Builder objects, so the Environment created above can not be used call Builders like env.Program(), env.Object(), env.StaticLibrary(), etc. .SS Adding Your Own Builder Object to an Environment .ES bld = Builder(action = 'pdftex < $SOURCES > $TARGET' suffix = '.pdf', src_suffix = '.tex') env = Environment() env.Append(BUILDERS = {'PDFBuilder' : bld}) env.PDFBuilder(target = 'foo.pdf', source = 'foo.tex') env.Program(target = 'bar', source = 'bar.c') .EE You also can use other Pythonic techniques to add to the BUILDERS construction variable, such as: .ES env = Environment() env['BUILDERS]['PDFBuilder'] = bld .EE .SS Defining Your Own Scanner Object .ES import re '\" Note: the \\ in the following are for the benefit of nroff/troff, '\" not inappropriate doubled escape characters within the r'' raw string. include_re = re.compile(r'^include\\s+(\\S+)$', re.M) def kfile_scan(node, env, path, arg): contents = node.get_contents() includes = include_re.findall(contents) return includes kscan = Scanner(name = 'kfile', function = kfile_scan, argument = None, skeys = ['.k']) scanners = Environment().Dictionary('SCANNERS') env = Environment(SCANNERS = scanners + [kscan]) env.Command('foo', 'foo.k', 'kprocess < $SOURCES > $TARGET') bar_in = File('bar.in') env.Command('bar', bar_in, 'kprocess $SOURCES > $TARGET') bar_in.target_scanner = kscan .EE .SS Creating a Hierarchical Build Notice that the file names specified in a subdirectory's SConscript file are relative to that subdirectory. .ES SConstruct: env = Environment() env.Program(target = 'foo', source = 'foo.c') SConscript('sub/SConscript') sub/SConscript: env = Environment() # Builds sub/foo from sub/foo.c env.Program(target = 'foo', source = 'foo.c') SConscript('dir/SConscript') sub/dir/SConscript: env = Environment() # Builds sub/dir/foo from sub/dir/foo.c env.Program(target = 'foo', source = 'foo.c') .EE .SS Sharing Variables Between SConscript Files You must explicitly Export() and Import() variables that you want to share between SConscript files. .ES SConstruct: env = Environment() env.Program(target = 'foo', source = 'foo.c') Export("env") SConscript('subdirectory/SConscript') subdirectory/SConscript: Import("env") env.Program(target = 'foo', source = 'foo.c') .EE .SS Building Multiple Variants From the Same Source Use the build_dir keyword argument to the SConscript function to establish one or more separate build directories for a given source directory: .ES SConstruct: cppdefines = ['FOO'] Export("cppdefines") SConscript('src/SConscript', build_dir='foo') cppdefines = ['BAR'] Export("cppdefines") SConscript('src/SConscript', build_dir='bar') src/SConscript: Import("cppdefines") env = Environment(CPPDEFINES = cppdefines) env.Program(target = 'src', source = 'src.c') .EE Note the use of the Export() method to set the "cppdefines" variable to a different value each time we call the SConscript function. .SS Hierarchical Build of Two Libraries Linked With a Program .ES SConstruct: env = Environment(LIBPATH = ['#libA', '#libB']) Export('env') SConscript('libA/SConscript') SConscript('libB/SConscript') SConscript('Main/SConscript') libA/SConscript: Import('env') env.Library('a', Split('a1.c a2.c a3.c')) libB/SConscript: Import('env') env.Library('b', Split('b1.c b2.c b3.c')) Main/SConscript: Import('env') e = env.Copy(LIBS = ['a', 'b']) e.Program('foo', Split('m1.c m2.c m3.c')) .EE The '#' in the LIBPATH directories specify that they're relative to the top-level directory, so they don't turn into "Main/libA" when they're used in Main/SConscript. Specifying only 'a' and 'b' for the library names allows SCons to append the appropriate library prefix and suffix for the current platform (for example, 'liba.a' on POSIX systems, 'a.lib' on Windows). .SS Customizing contruction variables from the command line. The following would allow the C compiler to be specified on the command line or in the file custom.py. .ES opts = Options('custom.py') opts.Add('CC', 'The C compiler.') env = Environment(options=opts) Help(opts.GenerateHelpText(env)) .EE The user could specify the C compiler on the command line: .ES scons "CC=my_cc" .EE or in the custom.py file: .ES CC = 'my_cc' .EE or get documentation on the options: .ES $ scons -h CC: The C compiler. default: None actual: cc .EE .SS Using Microsoft Visual C++ precompiled headers Since windows.h includes everything and the kitchen sink, it can take quite some time to compile it over and over again for a bunch of object files, so Microsoft provides a mechanism to compile a set of headers once and then include the previously compiled headers in any object file. This technology is called precompiled headers. The general recipe is to create a file named "StdAfx.cpp" that includes a single header named "StdAfx.h", and then include every header you want to precompile in "StdAfx.h", and finally include "StdAfx.h" as the first header in all the source files you are compiling to object files. For example: StdAfx.h: .ES #include #include .EE StdAfx.cpp: .ES #include .EE Foo.cpp: .ES #include /* do some stuff */ .EE Bar.cpp: .ES #include /* do some other stuff */ .EE SConstruct: .ES env=Environment() env['PCHSTOP'] = 'StdAfx.h' env['PCH'] = env.PCH('StdAfx.cpp')[0] env.Program('MyApp', ['Foo.cpp', 'Bar.cpp']) .EE For more information see the document for the PCH builder, and the PCH and PCHSTOP construction variables. To learn about the details of precompiled headers consult the MSDN documention for /Yc, /Yu, and /Yp. .SS Using Microsoft Visual C++ external debugging information Since including debugging information in programs and shared libraries can cause their size to increase significantly, Microsoft provides a mechanism for including the debugging information in an external file called a PDB file. SCons supports PDB files through the PDB construction variable. SConstruct: .ES env=Environment() env['PDB'] = 'MyApp.pdb' env.Program('MyApp', ['Foo.cpp', 'Bar.cpp']) .EE For more information see the document for the PDB construction variable. .SH ENVIRONMENT .IP SCONS_LIB_DIR Specifies the directory that contains the SCons Python module directory (e.g. /home/aroach/scons-src-0.01/src/engine). .IP SCONSFLAGS A string of options that will be used by scons in addition to those passed on the command line. .SH "SEE ALSO" .B scons User Manual, .B scons Design Document, .B scons source code. .SH AUTHORS Steven Knight .br Anthony Roach