2 # __FILE__ __REVISION__ __DATE__ __DEVELOPER__
5 SCons - a software construction tool
10 This is a beta release of SCons, a tool for building software (and other
11 files). SCons is implemented in Python, and its "configuration files"
12 are actually Python scripts, allowing you to use the full power of a
13 real scripting language to solve build problems. You do not, however,
14 need to know Python to use SCons effectively.
16 So that everyone using SCons can help each other learn how to use it
17 more effectively, please sign up for the scons-users mailing list at:
19 http://lists.sourceforge.net/lists/listinfo/scons-users
25 This is the seventh beta release of SCons. Please consult the
26 CHANGES.txt file for a list of specific changes since last release.
28 Please note the following important changes since release 0.95:
30 - The SConsignFile() function now uses an internally-supplied
31 SCons.dblite module as the default DB scheme for the .sconsign file.
32 If you are using the SConsignFile() function without an explicitly
33 specified dbm_module argument, this will cause all of your targets
34 to be recompiled the first time you use SCons 0.96. To preserve the
35 previous behavior, specify the "anydbm" module explicitly:
38 SConsignFile('.sconsign_file_name', anydbm)
40 - The scan_check function that can be supplied to a custom Scanner now
41 must take two arguments, the Node to be checked and a construction
42 environment. It previously only used the Node as an argument.
44 - The internal Scanner.add_skey() method no longer works for the
45 default scanners, which now use construction variables to hold their
46 lists of suffixes. If you had a custom Tool specification that was
47 reaching into the internals in this way to add a suffix to one of
48 the following scanner, you must now add the suffix to a construction
49 environment through which you plan to call the scanner, as follows:
52 CScan.add_skey('.x') => env.Append(CPPSUFFIXES = ['.x'])
53 DScan.add_skey('.x') => env.Append(DSUFFIXES = ['.x'])
54 FortranScan.add_skey('.x') => env.Append(FORTRANSUFFIXES = ['.x'])
56 - The internal "node_factory" keyword argument has been removed;
57 the seperate and more flexible "target_factory" and "source_factory"
58 keywords should be used instead.
60 - The behavior of the env.Append() and env.Prepend() methods has
61 changed when appending a string value to a UserList, or vice versa.
62 They now behave like normal Python addition of a string to
63 a UserList. Given an initialization and an env.Append() call like:
65 env = Environment(VAR1=UserList(['foo']), VAR2='foo')
66 env.Append(VAR1='bar', VAR2=UserList(['bar'])
68 The resulting values of $VAR1 and $VAR2 will now be ['foo', 'b',
69 'a', 'r'] and ['f', 'o', 'o', 'bar'], respectively. This is because
70 Python UserList objects treat strings as sequences of letters when
71 adding them to the value of the UserList.
73 The old behavior of yielding $VAR1 and $VAR2 values of ['foo',
74 'bar'] when either variable is a UserList object now requires that
75 the string variables be enclosed in a list:
77 env = Environment(VAR1=UserList(['foo']), VAR2=['foo'])
78 env.Append(VAR1='bar', VAR2=UserList(['bar']))
80 Note that the SCons behavior when appending to normal lists has
81 *not* changed, and the behavior of all of the default values that
82 SCons uses to initialize all construction variables has *not*
83 changed. This change *only* affects any cases where you explicitly
84 use UserList objects to initialize or append to a variable.
86 Please note the following important changes since release 0.94:
88 - The internal Python function used by the Zip Builder in Python
89 releases 1.6 or later now compresses the resulting .zip file
90 by default. The old behavior of creating an uncompressed file
91 may be preserved by setting the new ZIPCOMPRESSION construction
92 variable to 0 (or zipfile.ZIP_STORED, if you import the
93 underlying zipfile module).
95 - The "overrides" keyword argument to calls to the Builder() function
96 used to create new Builder objects has been deprecated and will
97 be removed in a future release. The items in an "overrides"
98 dictionary should now be specified as keyword arguments:
100 # Old way, "overrides" is a dictionary:
101 Builder(action = 'cp $TDIR/$TARGET $SDIR/$SOURCE',
102 overrides = {'TDIR' : dir1, 'SDIR' : dir2})
104 # New way, items are specified as keyword arguments:
105 Builder(action = 'cp $TDIR/$TARGET $SDIR/$SOURCE',
106 TDIR = dir1, SDIR = dir2)
108 - The meaning of some of the values of the "mode" argument to
109 the SCons.Util.scons_subst() and SCons.Util.scons_subst_list()
110 functions have been swapped. The wrapper Environment.subst() and
111 Environment.subst_list() methods remain completely unchanged, so
112 this should have no external effect. (We've listed the change here
113 because it might cause a problem if you're reaching into the SCons
114 internals and calling either of these SCons.Util functions directly.)
116 Please note the following FUTURE changes that you may wish to prepare
119 - When compiling with Microsoft Visual Studio, SCons currently adds
120 the ATL and MFC directories to the INCLUDE and LIB environment
121 variables by default. This default behavior will be changed in
122 a future release; the current plan is to change it for the 0.97
123 release (next release).
125 Whether or not the ATL and MFC directories are added to these
126 environment variables is now controlled by a new MSVS_USE_MFC_DIRS
127 *construction* variable. Setting this variable to a non-zero
128 value when you initialize an Environment will ensure that these
129 directories will be included in your external path(s) even when
130 the default behavior changes:
132 env = Environment(MSVS_USE_MFC_DIRS = 1)
134 The MSVS_USE_MFC_DIRS variable may, of course, be set to 0 (or
135 None) to prevent SCons from adding the ATL and MFC directories to
136 the INCLUDE and LIB environment variables.
138 SCons is developed with an extensive regression test suite, and a
139 rigorous development methodology for continually improving that suite.
140 Because of this, SCons is of sufficient quality that you can use it
141 for real work. The "beta" status of the release reflects that we
142 still may change interfaces in future releases, which may require
143 modifications to your SConscript files. We strive to hold these
144 changes to a minimum.
146 Nevertheless, please heed the following disclaimers:
148 - Please report any bugs or other problems that you find to our bug
149 tracker at our SourceForge project page:
151 http://sourceforge.net/tracker/?func=add&group_id=30337&atid=398971
153 We have a reliable bug-fixing methodology already in place and
154 strive to respond to problems relatively quickly.
156 - Documentation is spottier than we'd like. You may need to dive
157 into the source code to figure out how to do something. Asking
158 questions on the scons-users mailing list is also welcome. We
159 will be addressing the documentation in upcoming releases, but
160 would be more than glad to have your assistance in correcting this
163 In particular, the "SCons Design" documentation on the SCons web
164 site is currently out of date, as we made significant changes to
165 portions of the interface as we figured out what worked and what
166 didn't during implementation.
168 - There may be performance issues. Improving SCons performance
169 is an ongoing priority. If you still find the performance
170 unacceptable, we would very much like to hear from you and learn
171 more about your configuration so we can optimize the right things.
173 - Error messages don't always exist where they'd be helpful.
174 Please let us know about any errors you ran into that would
175 have benefitted from a (more) descriptive message.
177 KNOWN PROBLEMS IN THIS RELEASE:
179 For a complete list of known problems, consult the SCons bug tracker
182 http://sourceforge.net/tracker/?atid=398971&group_id=30337&func=browse
184 - Support for parallel builds (-j) does not work on WIN32 systems
185 prior to *official* Python release 2.2 (not 2.2 pre-releases).
187 Prior to Python 2.2, there is a bug in Python's Win32
188 implementation such that when a thread spawns an external command,
189 it blocks all threads from running. This breaks the SCons
190 multithreading architecture used to support -j builds.
192 We have included a patch file, os_spawnv_fix.diff, that you can
193 use if you you want to fix your version of Python to support
194 parallel builds in SCons.
196 - Again, the "SCons Design" documentation on the SCons web
197 site is currently out of date. Take what you read there with a
200 - If a file is specified to be built in multiple ways, the last
201 processed builder specification overwrites all other builders,
204 - On Win32 systems, you must put a space between the redirection
205 characters < and >, and the specified files (or construction
206 variable expansions):
208 command < $SOURCE > $TARGET
210 If you don't supply a space (for example, "<$SOURCE"), SCons will
211 not recognize the redirection.
213 - People have reported problems with SCons not stopping a build when
214 an interrupt (CTRL+C) is received. A fix was checked in to 0.11
215 that should fix this behavior on many systems, but there are
216 issues with the underlying Python os.system() call that suggest
217 this fix does not work on all systems or in all circumstances.
218 We're working to try to find a universal solution.
220 - Modifying a construction environment in a subsidiary SConscript
221 file modifies the global environment.
223 - MSVC .res files are not rebuilt when icons change.
225 - The -c option does not clean up .sconsign files or directories
226 created as part of the build, and also does not clean up
227 SideEffect files (for example, Visual Studio .pdb files).
229 - Switching content signatures from "MD5" to "timestamp" and back
230 again can cause unusual errors. These errors can be cleared up by
231 removing all .sconsign files.
233 - When using multiple Repositories, changing the name of an include
234 file can cause an old version of the file to be used.
236 - There is currently no way to force use of a relative path (../*)
237 for directories outside the top-level SConstruct file.
239 - The Jar() Builder will, on its second or subsequent invocation,
240 package up the .sconsign files that SCons uses to track signatures.
241 You can work around this by using the SConsignFile() function
242 to collect all of the .sconsign information into a single file
243 outside of the directory being packaged by Jar().
245 - SCons does not currently have a way to detect that an intermediate
246 file has been corrupted from outside and should be rebuilt.
248 - Unicode characters in path names do not work in all circumstances.
250 - A stray source file in a BuildDir can prevent targets from being
251 (re)built when they should.
253 - SCons does not automatically rebuild LaTeX files when the file
254 has an undefined reference on the first build.
256 - SideEffect() files are not retrieved properly from a CacheDir(),
257 and can lead to a stack trace.
259 - Use of --implicit-cache with TargetSignatures('content') can,
260 for some changes, not rebuild a file when necessary.
262 - SCons does not currently automatically check out SConstruct or
263 SConscript files from SCCS, RCS or BitKeeper.
265 - The Command() global function (specified without a construction
266 environment) is broken.
268 - No support yet for the following planned command-line options:
270 -d -e -l --list-actions --list-derived --list-where
271 -o --override -p -r -R -w --write-filenames
272 -W --warn-undefined-variables
276 Thank you for your interest, and please let us know how we can help
277 improve SCons for your needs.
280 knight at baldmt dot com
281 http://www.baldmt.com/~knight/
283 With plenty of help from the SCons Development team: