Param: comedi_t * device
Param: unsigned int subdevice
Description:
- The function comedi_cancel() can be used to stop a command
+ The function <function>comedi_cancel</function> can be used to stop a command
previously started by
- <link linkend="func-ref-comedi-command"><function>comedi_command</function></link>
+ <function><link linkend="func-ref-comedi-command">comedi_command</link></function>
which is still in progress
- on the subdevice indicated by the parameters <parameter>device</parameter>
- and <parameter>subdevice</parameter>.
+ on the subdevice indicated by the parameters <parameter class="function">device</parameter>
+ and <parameter class="function">subdevice</parameter>.
Returns:
- If successful, 0 is returned, otherwise -1.
+ If successful, <literal>0</literal> is returned, otherwise
+ <literal>-1</literal>.
Function: comedi_command -- start streaming input/output
Retval: int
Param: comedi_t * device
Param: comedi_cmd * command
Description:
- The function comedi_command() starts a streaming input
+ The function <function>comedi_command</function> starts a streaming input
or output. The
- command structure *<parameter>command</parameter> specifies
+ command structure pointed to by <parameter class="function">command</parameter> specifies
settings for the
acquisition. The command must be able to pass
- <link linkend="func-ref-comedi-command-test"><function>comedi_command_test</function></link>
- with a return value of 0, or comedi_command() will fail.
+ <function><link
+ linkend="func-ref-comedi-command-test">comedi_command_test</link></function>
+ with a return value of <literal>0</literal>, or
+ <function>comedi_command</function> will fail.
For input subdevices, sample values are read using the
- function read() on the device file. For output subdevices, sample values are written
- using the function write().
+ function <function>read</function> on the device file. For output subdevices,
+ sample values are written using the function <function>write</function>.
Returns:
- If successful, 0 is returned, otherwise -1.
+ If successful, <literal>0</literal> is returned, otherwise
+ <literal>-1</literal>.
Function: comedi_command_test -- test streaming input/output configuration
Retval: int
Param: comedi_t * device
Param: comedi_cmd * command
Description:
- The function comedi_command_test() tests the command structure pointed
- to by the parameter <parameter>command</parameter> and returns an
+ The function <function>comedi_command_test</function> tests the command structure pointed
+ to by the parameter <parameter class="function">command</parameter> and returns an
integer describing the
testing stages that were successfully passed. In addition, if elements
- of the *<parameter>command</parameter> structure are invalid, they may be modified. Source
+ of the <type>comedi_cmd</type> structure are invalid, they may be modified. Source
elements are modified to remove invalid source triggers. Argument
elements are adjusted or rounded to the nearest valid value.
<itemizedlist>
<listitem>
- <para>0 indicates a valid command.</para>
+ <para><literal>0</literal> indicates a valid command.</para>
</listitem>
<listitem>
<para>
- 1 indicates that one of the *_src
+ <literal>1</literal> indicates that one of the
+ <structfield>…_src</structfield>
members of the command contained an
unsupported trigger. The bits corresponding to the unsupported
triggers are zeroed.
</listitem>
<listitem>
<para>
- 2 indicates that the particular combination
- of *_src settings is not supported by the driver, or that
- one of the *_src members has the bit corresponding to
+ <literal>2</literal> indicates that the particular combination
+ of <structfield>…_src</structfield> settings is not supported by the driver, or that
+ one of the <structfield>…_src</structfield> members has the bit corresponding to
multiple trigger sources set at the same time.
</para>
</listitem>
<listitem>
<para>
- 3 indicates that one of the *_arg members
+ <literal>3</literal> indicates that one of the
+ <structfield>…_arg</structfield> members
of the command is set outside the range of allowable values.
- For instance, an argument for a TRIG_TIMER source which
- exceeds the board's maximum speed. The invalid *_arg
+ For instance, an argument for a
+ <constant>TRIG_TIMER</constant> source which
+ exceeds the board's maximum speed. The invalid
+ <structfield>…_arg</structfield>
members will be adjusted to valid values.
</para>
</listitem>
<listitem>
<para>
- 4 indicates that one of the *_arg members
+ <literal>4</literal> indicates that one of the
+ <structfield>…_arg</structfield> members
required adjustment. For instance, the argument of a
- TRIG_TIMER source may have been rounded to the nearest
+ <constant>TRIG_TIMER</constant> source may have been rounded to the nearest
timing period supported by the board.
</para>
</listitem>
<listitem>
<para>
- 5 indicates that some aspect of the
- command's chanlist is unsupported by the board. For example,
+ <literal>5</literal> indicates that some aspect of the
+ command's <structfield>chanlist</structfield> is unsupported by the board. For example,
some analog input boards require that all channels in the chanlist
use the same input range.
</para>
Param: comedi_t * device
Param: unsigned int subdevice
Description:
- The function comedi_get_buffer_contents() is used on a subdevice
+ The function <function>comedi_get_buffer_contents</function> is used on a subdevice
that has a Comedi command in progress. The number of bytes that
are available in the streaming buffer is returned. If there is
- an error, -1 is returned.
+ an error, <literal>-1</literal> is returned.
Function: comedi_get_buffer_offset -- streaming buffer status
Retval: int
Param: comedi_t * device
Param: unsigned int subdevice
Description:
- The function comedi_get_buffer_offset() is used on a subdevice
+ The function <function>comedi_get_buffer_offset</function> is used on a subdevice
that has a Comedi command in progress. This function returns
the offset in bytes of the read pointer in the streaming buffer.
This offset is only useful for memory mapped buffers.
- If there is an error, -1 is returned.
+ If there is an error, <literal>-1</literal> is returned.
Function: comedi_get_buffer_size -- streaming buffer size of subdevice
Retval: int
Param: comedi_t * device
Param: unsigned int subdevice
Description:
- The function comedi_get_buffer_size() returns the size (in bytes)
+ The function <function>comedi_get_buffer_size</function> returns the size (in bytes)
of the streaming buffer for the subdevice specified by
- <parameter>device</parameter> and
- <parameter>subdevice</parameter>. On error, -1 is returned.
+ <parameter class="function">device</parameter> and
+ <parameter class="function">subdevice</parameter>.
+ On error, <literal>-1</literal> is returned.
Function: comedi_get_cmd_generic_timed -- streaming input/output capabilities
Retval: int
Param: unsigned int scan_period_ns
Description:
The command capabilities of the subdevice indicated by the parameters
- <parameter>device</parameter> and <parameter>subdevice</parameter>
+ <parameter class="function">device</parameter> and <parameter
+ class="function">subdevice</parameter>
are probed, and the results placed in the
- command structure pointed to by the parameter command. The command
- structure *<parameter>command</parameter> is modified to be a
+ command structure pointed to by the parameter <parameter
+ class="function">command</parameter>.
+ The command structure pointed to by <parameter class="function">command</parameter>
+ is modified to be a
valid command that can be used as a parameter to
- <link linkend="func-ref-comedi-command"><function>comedi_command</function></link>
- (after the command has additionally been assigned a valid chanlist array).
- The command measures scans consisting of <parameter>chanlist_len</parameter>
+ <function><link linkend="func-ref-comedi-command">comedi_command</link></function>
+ (after the command has additionally been assigned a valid
+ <structfield>chanlist</structfield> array).
+ The command measures scans consisting of <parameter class="function">chanlist_len</parameter>
channels
at a scan rate that corresponds to a period of
- <parameter>scan_period_ns</parameter> nanoseconds.
+ <parameter class="function">scan_period_ns</parameter> nanoseconds.
The rate is adjusted to a rate that the device
can handle.
Returns:
- If successful, 0 is returned, otherwise -1.
+ If successful, <literal>0</literal> is returned, otherwise
+ <literal>-1</literal>.
Function: comedi_get_cmd_src_mask -- streaming input/output capabilities
Retval: int
Param: comedi_cmd * command
Description:
The command capabilities of the subdevice indicated by the parameters
- <parameter>device</parameter> and <parameter>subdevice</parameter>
+ <parameter class="function">device</parameter> and <parameter
+ class="function">subdevice</parameter>
are probed, and the results placed in the
- command structure *<parameter>command</parameter>. The trigger
+ command structure pointed to by <parameter class="function">command</parameter>. The trigger
source elements of the command structure are set to be the bitwise-or
of the subdevice's supported trigger sources. Other elements in the structure
are undefined.
Returns:
- If successful, 0 is returned, otherwise -1.
+ If successful, <literal>0</literal> is returned, otherwise
+ <literal>-1</literal>.
Function: comedi_get_max_buffer_size -- maximum streaming buffer size
Retval: int
Param: comedi_t * device
Param: unsigned int subdevice
Description:
- The function comedi_get_max_buffer_size() returns the maximum
+ The function <function>comedi_get_max_buffer_size</function> returns the maximum
allowable size (in bytes) of the streaming buffer for the subdevice
- specified by <parameter>device</parameter> and <parameter>subdevice</parameter>.
+ specified by <parameter class="function">device</parameter>
+ and <parameter class="function">subdevice</parameter>.
Changing the maximum buffer
size can be accomplished with
- <link linkend="func-ref-comedi-set-max-buffer-size"><function>comedi_set_max_buffer_size</function></link>
- or with the comedi_config program,
- and requires appropriate privileges. On error, -1 is returned.
+ <function><link
+ linkend="func-ref-comedi-set-max-buffer-size">comedi_set_max_buffer_size</link></function>
+ or with the <command>comedi_config</command> program,
+ and requires appropriate privileges. On error, <literal>-1</literal> is returned.
Function: comedi_get_read_subdevice -- find streaming input subdevice
Retval: int
Param: comedi_t * device
Description:
- The function comedi_get_read_subdevice() returns the subdevice
+ The function <function>comedi_get_read_subdevice</function> returns the
+ index of the subdevice
whose streaming input buffer is accessible through the
- device <parameter>dev</parameter>. If
- there is no such subdevice, -1 is returned.
+ device <parameter class="function">device</parameter>. If
+ there is no such subdevice, <literal>-1</literal> is returned.
Function: comedi_get_write_subdevice -- find streaming output subdevice
Retval: int
Param: comedi_t * device
Description:
- The function comedi_get_write_subdevice() returns the subdevice
+ The function <function>comedi_get_write_subdevice</function> returns the
+ index of the subdevice
whose streaming output buffer is accessible through the
- device <parameter>dev</parameter>. If there is no such subdevice,
- -1 is returned.
+ device <parameter class="device">device</parameter>. If there is no such subdevice,
+ <literal>-1</literal> is returned.
Function: comedi_mark_buffer_read -- streaming buffer control
Retval: int
Param: unsigned int subdevice
Param: unsigned int num_bytes
Description:
- The function comedi_mark_buffer_read() is used on a subdevice
+ The function <function>comedi_mark_buffer_read</function> is used on a subdevice
that has a Comedi input command in progress. It should only be used
- if you are using a mmap() to read data from Comedi's buffer
- (as opposed to calling read() on the device file),
+ if you are using a <function>mmap</function> mapping to read data from Comedi's buffer
+ (as opposed to calling <function>read</function> on the device file),
since Comedi will automatically keep track of how many bytes have been
- transferred via read() calls. This function is
- used to indicate that the next <parameter>num_bytes</parameter>
+ transferred via <function>read</function> calls. This function is
+ used to indicate that the next <parameter class="function">num_bytes</parameter>
bytes in the buffer
are no longer needed and may be discarded.
Returns:
The function <function>comedi_mark_buffer_read</function> returns the
number of bytes successfully marked as read,
- or -1 on error. The return value may be less than
- <parameter>num_bytes</parameter> if you attempt to mark more
+ or <literal>-1</literal> on error. The return value may be less than
+ <parameter class="function">num_bytes</parameter> if you attempt to mark more
bytes read than are currently available for reading, or
- if <parameter>num_bytes</parameter> must be rounded down
+ if <parameter class="function">num_bytes</parameter> must be rounded down
to be an exact multiple of the subdevice's
- sample size (either sizeof(sampl_t) or sizeof(lsampl_t)).
+ sample size (either <code language="C">sizeof(sampl_t)</code> or
+ <code language="C">sizeof(lsampl_t)</code>).
Function: comedi_mark_buffer_written -- streaming buffer control
Retval: int
Param: unsigned int subdevice
Param: unsigned int num_bytes
Description:
- The function comedi_mark_buffer_written() is used on a subdevice
+ The function <function>comedi_mark_buffer_written</function> is used on a subdevice
that has a Comedi output command in progress. It should only be used
- if you are using a mmap() to write data to Comedi's buffer
- (as opposed to calling write() on the device
+ if you are using a <function>mmap</function> mapping to write data to Comedi's buffer
+ (as opposed to calling <function>write</function> on the device
file), since Comedi
will automatically keep track of how many bytes have been
- transferred via write() calls. This function is
- used to indicate that the next <parameter>num_bytes</parameter>
+ transferred via <function>write</function> calls. This function is
+ used to indicate that the next <parameter class="function">num_bytes</parameter>
bytes in the buffer
are valid and may be sent to the device.
Returns:
The function <function>comedi_mark_buffer_written</function> returns
number of bytes successfully marked as written,
- or -1 on error. The return value may be less than
- <parameter>num_bytes</parameter> if you attempt to mark more
+ or <literal>-1</literal> on error. The return value may be less than
+ <parameter class="function">num_bytes</parameter> if you attempt to mark more
bytes written than the amount of free space currently available
in the output buffer, or
- if <parameter>num_bytes</parameter> must be
+ if <parameter class="function">num_bytes</parameter> must be
rounded down to be an exact multiple of the subdevice's
- sample size (either sizeof(sampl_t) or sizeof(lsampl_t)).
+ sample size (either <code language="C">sizeof(sampl_t)</code>
+ or <code language="C">sizeof(lsampl_t)</code>).
Function: comedi_poll -- force updating of streaming buffer
Retval: int
Param: comedi_t * device
Param: unsigned int subdevice
Description:
- The function comedi_poll() is used on a subdevice that has a
+ The function <function>comedi_poll</function> is used on a subdevice that has a
Comedi command in progress in order to update the streaming buffer.
If supported by the driver, all available samples are copied to
the streaming buffer. These samples may be pending in DMA buffers
or device FIFOs. If successful, the number of additional bytes
- available is returned. If there is an error, -1 is returned.
+ available is returned. If there is an error, <literal>-1</literal> is returned.
Function: comedi_set_buffer_size -- streaming buffer size of subdevice
Retval: int
Param: unsigned int subdevice
Param: unsigned int size
Description:
- The function comedi_set_buffer_size() changes the size of the
+ The function <function>comedi_set_buffer_size</function> changes the size of the
streaming buffer for the subdevice specified by
- <parameter>device</parameter> and <parameter>subdevice</parameter>.
- The buffer size will be set to <parameter>size</parameter> bytes,
+ <parameter class="function">device</parameter> and <parameter
+ class="function">subdevice</parameter>.
+ The buffer size will be set to <parameter class="function">size</parameter> bytes,
rounded up to a multiple of the virtual memory page
size. The virtual memory page size can be determined using
- sysconf(_SC_PAGE_SIZE).
+ <code language="C">sysconf(_SC_PAGE_SIZE)</code>.
This function does not require special privileges. However,
it is limited to a (adjustable) maximum buffer size, which can
- be changed by a priveliged user calling
- <link linkend="func-ref-comedi-set-max-buffer-size"><function>comedi_set_max_buffer_size</function></link>,
- or running the program comedi_config.
+ be changed by a privileged user calling
+ <function><link
+ linkend="func-ref-comedi-set-max-buffer-size">comedi_set_max_buffer_size</link></function>,
+ or running the program <command>comedi_config</command>.
Returns:
The new buffer size in bytes is returned on success. On error,
- -1 is returned.
+ <literal>-1</literal> is returned.
-Function: comedi_set_max_buffer_size -- streaming buffer size of subdevice
+Function: comedi_set_max_buffer_size -- streaming maximum buffer size of subdevice
Retval: int
Param: comedi_t * device
Param: unsigned int subdevice
Param: unsigned int max_size
Description:
- The function comedi_set_max_buffer_size() changes the maximum
+ The function <function>comedi_set_max_buffer_size</function> changes the maximum
allowable size (in bytes) of the streaming buffer for the subdevice
- specified by device and subdevice. Changing the maximum buffer
+ specified by <parameter class="function">device</parameter> and
+ <parameter class="function">subdevice</parameter>. Changing the maximum buffer
size requires the user to have appropriate privileges.
Returns:
- The old buffer size is returned on success. On error, -1 is returned.
+ The new maximum buffer size is returned on success. On error, <literal>-1</literal> is returned.
projects / comedilib.git / commitdiff