xbd_chap02.html

IEEE 1003.1-2003, Single Unix Specification v3

_POSIX_MEMLOCK_RANGE

_POSIX_MEMORY_PROTECTION

_POSIX_MESSAGE_PASSING

_POSIX_PRIORITIZED_IO

_POSIX_PRIORITY_SCHEDULING

_POSIX_REALTIME_SIGNALS

_POSIX_SEMAPHORES

_POSIX_SHARED_MEMORY_OBJECTS

_POSIX_SYNCHRONIZED_IO

_POSIX_TIMERS

</pre>
</blockquote>

<p>If the symbolic constant _XOPEN_REALTIME is defined to have a value other than -1, then the following symbolic constants shall
be defined by the implementation to have the value 200112L:</p>

<blockquote>
<pre>
_POSIX_ASYNCHRONOUS_IO

_POSIX_MEMLOCK

_POSIX_MEMLOCK_RANGE

_POSIX_MESSAGE_PASSING

_POSIX_PRIORITY_SCHEDULING

_POSIX_REALTIME_SIGNALS

_POSIX_SEMAPHORES

_POSIX_SHARED_MEMORY_OBJECTS

_POSIX_SYNCHRONIZED_IO

_POSIX_TIMERS

</pre>
</blockquote>

<p>The functionality associated with _POSIX_MAPPED_FILES, _POSIX_MEMORY_PROTECTION, and _POSIX_FSYNC is always supported on
XSI-conformant systems.</p>

<p>Support of _POSIX_PRIORITIZED_IO on XSI-conformant systems is optional. If this functionality is supported, then
_POSIX_PRIORITIZED_IO shall be set to a value other than -1. Otherwise, it shall be undefined.</p>

<p>If _POSIX_PRIORITIZED_IO is supported, then asynchronous I/O operations performed by <a href=
"../functions/aio_read.html"><i>aio_read</i>()</a>, <a href="../functions/aio_write.html"><i>aio_write</i>()</a>, and <a href=
"../functions/lio_listio.html"><i>lio_listio</i>()</a> shall be submitted at a priority equal to the scheduling priority of the
process minus <i>aiocbp</i>-&gt;<i>aio_reqprio</i>. The implementation shall also document for which files I/O prioritization is
supported.</p>

<h5><a name="tag_02_01_05_05"></a>Advanced Realtime</h5>

<p>An implementation that claims conformance to this Option Group shall also support the Realtime Option Group.</p>

<p>Where entire functions are included in the Option Group, the NAME section is marked with ADVANCED REALTIME. Where additional
semantics have been added to existing pages, the new material is identified by use of the appropriate margin legend for the
underlying option defined within IEEE&nbsp;Std&nbsp;1003.1-2001.</p>

<p>This Option Group consists of the set of the following options from within IEEE&nbsp;Std&nbsp;1003.1-2001 (see <a href=
"#tag_02_01_06">Options</a> ):</p>

<blockquote>
<pre>
_POSIX_ADVISORY_INFO

_POSIX_CLOCK_SELECTION

_POSIX_CPUTIME

_POSIX_MONOTONIC_CLOCK

_POSIX_SPAWN

_POSIX_SPORADIC_SERVER

_POSIX_TIMEOUTS

_POSIX_TYPED_MEMORY_OBJECTS

</pre>
</blockquote>

<p>If the implementation supports the Advanced Realtime Option Group, then the following symbolic constants shall be defined by the
implementation to have the value 200112L:</p>

<blockquote>
<pre>
_POSIX_ADVISORY_INFO

_POSIX_CLOCK_SELECTION

_POSIX_CPUTIME

_POSIX_MONOTONIC_CLOCK

_POSIX_SPAWN

_POSIX_SPORADIC_SERVER

_POSIX_TIMEOUTS

_POSIX_TYPED_MEMORY_OBJECTS

</pre>
</blockquote>

<p>If the symbolic constant _POSIX_SPORADIC_SERVER is defined, then the symbolic constant _POSIX_PRIORITY_SCHEDULING shall also be
defined by the implementation to have the value 200112L.</p>

<p>If the symbolic constant _POSIX_CPUTIME is defined, then the symbolic constant _POSIX_TIMERS shall also be defined by the
implementation to have the value 200112L.</p>

<p>If the symbolic constant _POSIX_MONOTONIC_CLOCK is defined, then the symbolic constant _POSIX_TIMERS shall also be defined by
the implementation to have the value 200112L.</p>

<p>If the symbolic constant _POSIX_CLOCK_SELECTION is defined, then the symbolic constant _POSIX_TIMERS shall also be defined by
the implementation to have the value 200112L.</p>

<h5><a name="tag_02_01_05_06"></a>Realtime Threads</h5>

<p>The Realtime Threads Option Group is denoted by the symbolic constant _XOPEN_REALTIME_THREADS.</p>

<p>This Option Group consists of the set of the following options from within IEEE&nbsp;Std&nbsp;1003.1-2001 (see <a href=
"#tag_02_01_06">Options</a> ):</p>

<blockquote>
<pre>
_POSIX_THREAD_PRIO_INHERIT

_POSIX_THREAD_PRIO_PROTECT

_POSIX_THREAD_PRIORITY_SCHEDULING

</pre>
</blockquote>

<p>Where applicable, whole pages are marked REALTIME THREADS, together with the appropriate option margin legend for the SYNOPSIS
section (see <a href="xbd_chap01.html#tag_01_05_01"><i>Codes</i></a> ).</p>

<p>An implementation that claims conformance to this Option Group shall set _XOPEN_REALTIME_THREADS to a value other than -1.</p>

<p>If the symbol _XOPEN_REALTIME_THREADS is defined to have a value other than -1, then the following options shall also be defined
by the implementation to have the value 200112L:</p>

<blockquote>
<pre>
_POSIX_THREAD_PRIO_INHERIT

_POSIX_THREAD_PRIO_PROTECT

_POSIX_THREAD_PRIORITY_SCHEDULING

</pre>
</blockquote>

<h5><a name="tag_02_01_05_07"></a>Advanced Realtime Threads</h5>

<p>An implementation that claims conformance to this Option Group shall also support the Realtime Threads Option Group.</p>

<p>Where entire functions are included in the Option Group, the NAME section is marked with ADVANCED REALTIME THREADS. Where
additional semantics have been added to existing pages, the new material is identified by use of the appropriate margin legend for
the underlying option defined within IEEE&nbsp;Std&nbsp;1003.1-2001.</p>

<p>This Option Group consists of the set of the following options from within IEEE&nbsp;Std&nbsp;1003.1-2001 (see <a href=
"#tag_02_01_06">Options</a> ):</p>

<blockquote>
<pre>
_POSIX_BARRIERS

_POSIX_SPIN_LOCKS

_POSIX_THREAD_CPUTIME

_POSIX_THREAD_SPORADIC_SERVER

</pre>
</blockquote>

<p>If the symbolic constant _POSIX_THREAD_SPORADIC_SERVER is defined to have the value 200112L, then the symbolic constant
_POSIX_THREAD_PRIORITY_SCHEDULING shall also be defined by the implementation to have the value 200112L.</p>

<p>If the symbolic constant _POSIX_THREAD_CPUTIME is defined to have the value 200112L, then the symbolic constant _POSIX_TIMERS
shall also be defined by the implementation to have the value 200112L.</p>

<p>If the symbolic constant _POSIX_BARRIERS is defined to have the value 200112L, then the symbolic constants _POSIX_THREADS and
_POSIX_THREAD_SAFE_FUNCTIONS shall also be defined by the implementation to have the value 200112L.</p>

<p>If the symbolic constant _POSIX_SPIN_LOCKS is defined to have the value 200112L, then the symbolic constants _POSIX_THREADS and
_POSIX_THREAD_SAFE_FUNCTIONS shall also be defined by the implementation to have the value 200112L.</p>

<p>If the implementation supports the Advanced Realtime Threads Option Group, then the following symbolic constants shall be
defined by the implementation to have the value 200112L:</p>

<blockquote>
<pre>
_POSIX_BARRIERS

_POSIX_SPIN_LOCKS

_POSIX_THREAD_CPUTIME

_POSIX_THREAD_SPORADIC_SERVER

</pre>
</blockquote>

<h5><a name="tag_02_01_05_08"></a>Tracing</h5>

<p>This Option Group includes a set of tracing functions drawn from options within IEEE&nbsp;Std&nbsp;1003.1-2001 (see <a href=
"#tag_02_01_06">Options</a> ).</p>

<p>Where entire functions are included in the Option Group, the NAME section is marked with TRACING. Where additional semantics
have been added to existing pages, the new material is identified by use of the appropriate margin legend for the underlying option
defined within IEEE&nbsp;Std&nbsp;1003.1-2001.</p>

<p>This Option Group consists of the set of the following options from within IEEE&nbsp;Std&nbsp;1003.1-2001 (see <a href=
"#tag_02_01_06">Options</a> ):</p>

<blockquote>
<pre>
_POSIX_TRACE

_POSIX_TRACE_EVENT_FILTER

_POSIX_TRACE_LOG

_POSIX_TRACE_INHERIT

</pre>
</blockquote>

<p>If the implementation supports the Tracing Option Group, then the following symbolic constants shall be defined by the
implementation to have the value 200112L:</p>

<blockquote>
<pre>
_POSIX_TRACE

_POSIX_TRACE_EVENT_FILTER

_POSIX_TRACE_LOG

_POSIX_TRACE_INHERIT

</pre>
</blockquote>

<h5><a name="tag_02_01_05_09"></a>XSI STREAMS</h5>

<p>The XSI STREAMS Option Group is denoted by the symbolic constant _XOPEN_STREAMS.</p>

<p>This Option Group includes functionality related to STREAMS, a uniform mechanism for implementing networking services and other
character-based I/O as described in the System Interfaces volume of IEEE&nbsp;Std&nbsp;1003.1-2001, <a href=
"../functions/xsh_chap02_06.html">Section 2.6, STREAMS</a>.</p>

<p>It includes the following functions:</p>

<blockquote><a href="../functions/fattach.html"><i>fattach</i>()</a>, <a href="../functions/fdetach.html"><i>fdetach</i>()</a>, <a
href="../functions/getmsg.html"><i>getmsg</i>()</a>, <a href="../functions/getpmsg.html"><i>getpmsg</i>()</a>, <a href=
"../functions/ioctl.html"><i>ioctl</i>()</a>, <a href="../functions/isastream.html"><i>isastream</i>()</a>, <a href=
"../functions/putmsg.html"><i>putmsg</i>()</a>, <a href="../functions/putpmsg.html"><i>putpmsg</i>()</a></blockquote>

<p>and the <a href="../basedefs/stropts.h.html"><i>&lt;stropts.h&gt;</i></a> header.</p>

<p>Where applicable, whole pages are marked STREAMS, together with the appropriate option margin legend for the SYNOPSIS section
(see <a href="xbd_chap01.html#tag_01_05_01"><i>Codes</i></a> ). Where additional semantics have been added to existing pages, the
new material is identified by use of the appropriate margin legend for the underlying option defined within
IEEE&nbsp;Std&nbsp;1003.1-2001.</p>

<p>An implementation that claims conformance to this Option Group shall set _XOPEN_STREAMS to a value other than -1.</p>

<h5><a name="tag_02_01_05_10"></a>Legacy</h5>

<p>The Legacy Option Group is denoted by the symbolic constant _XOPEN_LEGACY.</p>

<p>The Legacy Option Group includes the functions and headers which were mandatory in previous versions of
IEEE&nbsp;Std&nbsp;1003.1-2001 but are optional in this version.</p>

<p>These functions and headers are retained in IEEE&nbsp;Std&nbsp;1003.1-2001 because of their widespread use. Application writers
should not rely on the existence of these functions or headers in new applications, but should follow the migration path detailed
in the APPLICATION USAGE sections of the relevant pages.</p>

<p>Various factors may have contributed to the decision to mark a function or header LEGACY. In all cases, the specific reasons for
the withdrawal of a function or header are documented on the relevant pages.</p>

<p>Once a function or header is marked LEGACY, no modifications are made to the specifications of such functions or headers other
than to the APPLICATION USAGE sections of the relevant pages.</p>

<p>The functions and headers which form this Option Group are as follows:</p>

<blockquote><a href="../functions/bcmp.html"><i>bcmp</i>()</a>, <a href="../functions/bcopy.html"><i>bcopy</i>()</a>, <a href=
"../functions/bzero.html"><i>bzero</i>()</a>, <a href="../functions/ecvt.html"><i>ecvt</i>()</a>, <a href=
"../functions/fcvt.html"><i>fcvt</i>()</a>, <a href="../functions/ftime.html"><i>ftime</i>()</a>, <a href=
"../functions/gcvt.html"><i>gcvt</i>()</a>, <a href="../functions/getwd.html"><i>getwd</i>()</a>, <a href=
"../functions/index.html"><i>index</i>()</a>, <a href="../functions/mktemp.html"><i>mktemp</i>()</a>, <a href=
"../functions/rindex.html"><i>rindex</i>()</a>, <a href="../functions/utimes.html"><i>utimes</i>()</a>, <a href=
"../functions/wcswcs.html"><i>wcswcs</i>()</a></blockquote>

<p>An implementation that claims conformance to this Option Group shall set _XOPEN_LEGACY to a value other than -1.</p>

<h4><a name="tag_02_01_06"></a>Options</h4>

<p>The symbolic constants defined in <a href="../basedefs/unistd.h.html"><i>&lt;unistd.h&gt;</i></a>, <a href=
"unistd.h.html"><i>Constants for Options and Option Groups</i></a> reflect implementation options for
IEEE&nbsp;Std&nbsp;1003.1-2001. These symbols can be used by the application to determine which optional facilities are present on
the implementation. The <a href="../functions/sysconf.html"><i>sysconf</i>()</a> function defined in the System Interfaces volume
of IEEE&nbsp;Std&nbsp;1003.1-2001 or the <a href="../utilities/getconf.html"><i>getconf</i></a> utility defined in the Shell and
Utilities volume of IEEE&nbsp;Std&nbsp;1003.1-2001 can be used to retrieve the value of each symbol on each specific implementation
to determine whether the option is supported.</p>

<p>Where an option is not supported, the associated utilities, functions, or facilities need not be present.</p>

<p>Margin codes are defined for each option (see <a href="xbd_chap01.html#tag_01_05_01"><i>Codes</i></a> ).</p>

<h5><a name="tag_02_01_06_01"></a>System Interfaces</h5>

<p>Refer to <a href="../basedefs/unistd.h.html"><i>&lt;unistd.h&gt;</i></a>, <a href="unistd.h.html"><i>Constants for Options and
Option Groups</i></a> for the list of options.</p>

<h5><a name="tag_02_01_06_02"></a>Shell and Utilities</h5>

<p>Each of these symbols shall be considered valid names by the implementation. Refer to <a href=
"../basedefs/unistd.h.html"><i>&lt;unistd.h&gt;</i></a>, <a href="unistd.h.html"><i>Constants for Options and Option Groups</i></a>
.</p>

<p>The literal names shown below apply only to the <a href="../utilities/getconf.html"><i>getconf</i></a> utility.</p>

<dl compact>
<dt>POSIX2_C_DEV</dt>

<dd><sup>[<a href="javascript:open_code('CD')">CD</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border=
"0"><br>
The system supports the C-Language Development Utilities option. <img src="../images/opt-end.gif" alt="[Option End]" border="0"> 

<p>The utilities in the C-Language Development Utilities option are used for the development of C-language applications, including
compilation or translation of C source code and complex program generators for simple lexical tasks and processing of context-free
grammars.</p>

<p>The utilities listed below may be provided by a conforming system; however, any system claiming conformance to the C-Language
Development Utilities option shall provide all of the utilities listed.</p>

<blockquote>
<pre>
<a href="../utilities/c99.html"><i>c99</i></a>
<a href="../utilities/lex.html"><i>lex</i></a>
<a href="../utilities/yacc.html"><i>yacc</i></a>
</pre>
</blockquote>
</dd>

<dt>POSIX2_CHAR_TERM</dt>

<dd><br>
The system supports the Terminal Characteristics option. This value need not be present on a system not supporting the User
Portability Utilities option. 

<p>Where applicable, the dependency is noted within the description of the utility.</p>

<p>This option applies only to systems supporting the User Portability Utilities option. If supported, then the system supports at
least one terminal type capable of all operations described in IEEE&nbsp;Std&nbsp;1003.1-2001; see <a href=
"xbd_chap10.html#tag_10_02"><i>Output Devices and Terminal Types</i></a> .</p>
</dd>