xbd_chap02.html

IEEE 1003.1-2003, Single Unix Specification v3

<li>
<p>POSIX2_CHAR_TERM</p>
</li>

<li>
<p>POSIX2_FORT_DEV</p>
</li>

<li>
<p>POSIX2_FORT_RUN</p>
</li>

<li>
<p>POSIX2_LOCALEDEF</p>
</li>

<li>
<p>POSIX2_PBS</p>
</li>

<li>
<p>POSIX2_PBS_ACCOUNTING</p>
</li>

<li>
<p>POSIX2_PBS_LOCATE</p>
</li>

<li>
<p>POSIX2_PBS_MESSAGE</p>
</li>

<li>
<p>POSIX2_PBS_TRACK</p>
</li>

<li>
<p>POSIX2_SW_DEV</p>
</li>

<li>
<p>POSIX2_UPE</p>
</li>
</ul>
</li>

<li>
<p>The system may support the XSI extensions (see <a href="#tag_02_01_04">XSI Conformance</a> ).</p>
</li>
</ul>

<p>Additional language bindings and development utility options may be provided in other related standards or in a future version
of IEEE&nbsp;Std&nbsp;1003.1-2001. In the former case, additional symbolic constants of the same general form as shown in this
subsection should be defined by the related standard document and made available to the application without requiring
IEEE&nbsp;Std&nbsp;1003.1-2001 to be updated.</p>

<h4><a name="tag_02_01_04"></a>XSI Conformance</h4>

<p><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
This section describes the criteria for implementations conforming to the XSI extension (see <a href=
"xbd_chap03.html#tag_03_439"><i>XSI</i></a> ). This functionality is dependent on the support of the XSI extension (and the rest of
this section is not further marked). <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>

<p>IEEE&nbsp;Std&nbsp;1003.1-2001 describes utilities, functions, and facilities offered to application programs by the X/Open
System Interface (XSI). An XSI-conforming implementation shall meet the criteria for POSIX conformance and the following
requirements.</p>

<h5><a name="tag_02_01_04_01"></a>XSI System Interfaces</h5>

<ul>
<li>
<p>The system shall support all the functions and headers defined in IEEE&nbsp;Std&nbsp;1003.1-2001 as part of the XSI extension
denoted by the symbolic constant _XOPEN_UNIX and any extensions marked with the XSI extension marking (see <a href=
"xbd_chap01.html#tag_01_05_01"><i>Codes</i></a> ).</p>
</li>

<li>
<p>The system shall support the <a href="../functions/mmap.html"><i>mmap</i>()</a>, <a href=
"../functions/munmap.html"><i>munmap</i>()</a>, and <a href="../functions/msync.html"><i>msync</i>()</a> functions.</p>
</li>

<li>
<p>The system shall support the following options defined within IEEE&nbsp;Std&nbsp;1003.1-2001 (see <a href=
"#tag_02_01_06">Options</a> ):</p>

<ul>
<li>
<p>_POSIX_FSYNC</p>
</li>

<li>
<p>_POSIX_MAPPED_FILES</p>
</li>

<li>
<p>_POSIX_MEMORY_PROTECTION</p>
</li>

<li>
<p>_POSIX_THREAD_ATTR_STACKADDR</p>
</li>

<li>
<p>_POSIX_THREAD_ATTR_STACKSIZE</p>
</li>

<li>
<p>_POSIX_THREAD_PROCESS_SHARED</p>
</li>

<li>
<p>_POSIX_THREAD_SAFE_FUNCTIONS</p>
</li>

<li>
<p>_POSIX_THREADS</p>
</li>
</ul>
</li>

<li>
<p>The system may support the following XSI Option Groups (see <a href="#tag_02_01_05_02">XSI Option Groups</a> ) defined within
IEEE&nbsp;Std&nbsp;1003.1-2001:</p>

<ul>
<li>
<p>Encryption</p>
</li>

<li>
<p>Realtime</p>
</li>

<li>
<p>Advanced Realtime</p>
</li>

<li>
<p>Realtime Threads</p>
</li>

<li>
<p>Advanced Realtime Threads</p>
</li>

<li>
<p>Tracing</p>
</li>

<li>
<p>XSI STREAMS</p>
</li>

<li>
<p>Legacy</p>
</li>
</ul>
</li>
</ul>

<h5><a name="tag_02_01_04_02"></a>XSI Shell and Utilities Conformance</h5>

<ul>
<li>
<p>The system shall support all the utilities defined in the Shell and Utilities volume of IEEE&nbsp;Std&nbsp;1003.1-2001 as part
of the XSI extension denoted by the XSI marking in the SYNOPSIS section, and any extensions marked with the XSI extension marking
(see <a href="xbd_chap01.html#tag_01_05_01"><i>Codes</i></a> ) within the text.</p>
</li>

<li>
<p>The system shall support the User Portability Utilities option.</p>
</li>

<li>
<p>The system shall support creation of locales (see <a href="xbd_chap07.html#tag_07"><i>Locale</i></a> ).</p>
</li>

<li>
<p>The C-language Development utility <a href="../utilities/c99.html"><i>c99</i></a> shall be supported.</p>
</li>

<li>
<p>The XSI Development Utilities option may be supported. It consists of the following software development utilities:</p>

<blockquote>
<table cellpadding="3">
<tr valign="top">
<td align="left">
<p class="tent"><br>
<a href="../utilities/admin.html"><i>admin</i></a><br>
<a href="../utilities/cflow.html"><i>cflow</i></a><br>
<a href="../utilities/ctags.html"><i>ctags</i></a><br>
<a href="../utilities/cxref.html"><i>cxref</i></a><br>
&nbsp;</p>
</td>
<td align="left">
<p class="tent"><br>
<a href="../utilities/delta.html"><i>delta</i></a><br>
<a href="../utilities/get.html"><i>get</i></a><br>
<a href="../utilities/m4.html"><i>m4</i></a><br>
<a href="../utilities/nm.html"><i>nm</i></a><br>
&nbsp;</p>
</td>
<td align="left">
<p class="tent"><br>
<a href="../utilities/prs.html"><i>prs</i></a><br>
<a href="../utilities/rmdel.html"><i>rmdel</i></a><br>
<a href="../utilities/sact.html"><i>sact</i></a><br>
<a href="../utilities/sccs.html"><i>sccs</i></a><br>
&nbsp;</p>
</td>
<td align="left">
<p class="tent"><br>
<a href="../utilities/unget.html"><i>unget</i></a><br>
<a href="../utilities/val.html"><i>val</i></a><br>
<a href="../utilities/what.html"><i>what</i></a><br>
&nbsp;</p>
</td>
</tr>
</table>
</blockquote>
</li>

<li>
<p>Within the utilities that are provided, functionality marked by the code OF (see <a href=
"xbd_chap01.html#tag_01_05_01"><i>Codes</i></a> ) need not be provided.</p>
</li>
</ul>

<h4><a name="tag_02_01_05"></a>Option Groups</h4>

<p>An Option Group is a group of related functions or options defined within the System Interfaces volume of
IEEE&nbsp;Std&nbsp;1003.1-2001.</p>

<p>If an implementation supports an Option Group, then the system shall support the functional behavior described herein.</p>

<p>If an implementation does not support an Option Group, then the system need not support the functional behavior described
herein.</p>

<h5><a name="tag_02_01_05_01"></a>Subprofiling Considerations</h5>

<p>Profiling standards supporting functional requirements less than that required in IEEE&nbsp;Std&nbsp;1003.1-2001 may subset both
mandatory and optional functionality required for POSIX Conformance (see <a href="#tag_02_01_03">POSIX Conformance</a> ) or XSI
Conformance (see <a href="#tag_02_01_04">XSI Conformance</a> ). Such profiles shall organize the subsets into Subprofiling Option
Groups.</p>

<p>The Rationale (Informative) volume of IEEE&nbsp;Std&nbsp;1003.1-2001, Appendix E, Subprofiling Considerations (Informative)
describes a representative set of such Subprofiling Option Groups for use by profiles applicable to specialized realtime systems.
IEEE&nbsp;Std&nbsp;1003.1-2001 does not require that the presence of Subprofiling Option Groups be testable at compile-time (as
symbols defined in any header) or at runtime (via <a href="../functions/sysconf.html"><i>sysconf</i>()</a> or <a href=
"../utilities/getconf.html"><i>getconf</i></a>).</p>

<p>A Subprofiling Option Group may provide basic system functionality that other Subprofiling Option Groups and other options
depend upon.<a href="#tag_foot_1"><sup><small>1</small></sup></a> If a profile of IEEE&nbsp;Std&nbsp;1003.1-2001 does not require
an implementation to provide a Subprofiling Option Group that provides features utilized by a required Subprofiling Option Group
(or option),<a href="#tag_foot_2"><sup><small>2</small></sup></a> the profile shall specify<a href=
"#tag_foot_3"><sup><small>3</small></sup></a> all of the following:</p>

<ul>
<li>
<p>Restricted or altered behavior of interfaces defined in IEEE&nbsp;Std&nbsp;1003.1-2001 that may differ on an implementation of
the profile</p>
</li>

<li>
<p>Additional behaviors that may produce undefined or unspecified results</p>
</li>

<li>
<p>Additional implementation-defined behavior that implementations shall be required to document in the profile's conformance
document</p>
</li>
</ul>

<p>if any of the above is a result of the profile not requiring an interface required by IEEE&nbsp;Std&nbsp;1003.1-2001.</p>

<p>The following additional rules shall apply to all profiles of IEEE&nbsp;Std&nbsp;1003.1-2001:</p>

<ul>
<li>
<p>Any application that conforms to that profile shall also conform to IEEE&nbsp;Std&nbsp;1003.1-2001 (that is, a profile shall not
require restricted, altered, or extended behaviors of an implementation of IEEE&nbsp;Std&nbsp;1003.1-2001).</p>
</li>

<li>
<p>Profiles are permitted to add additional requirements to the limits defined in <a href=
"../basedefs/limits.h.html"><i>&lt;limits.h&gt;</i></a> and <a href="../basedefs/stdint.h.html"><i>&lt;stdint.h&gt;</i></a>,
subject to the following:</p>

<p>For the limits in <a href="../basedefs/limits.h.html"><i>&lt;limits.h&gt;</i></a> and <a href=
"../basedefs/stdint.h.html"><i>&lt;stdint.h&gt;</i></a>:</p>

<ul>
<li>
<p>If the limit is specified as having a fixed value, it shall not be changed by a profile.</p>
</li>

<li>
<p>If a limit is specified as having a minimum or maximum acceptable value, it may be changed by a profile as follows:</p>

<ul>
<li>
<p>A profile may increase a minimum acceptable value, but shall not make a minimum acceptable value smaller.</p>
</li>

<li>
<p>A profile may reduce a maximum acceptable value, but shall not make a maximum acceptable value larger.</p>
</li>
</ul>
</li>
</ul>
</li>

<li>
<p>A profile shall not change a limit specified as having a minimum or maximum value into a limit specified as having a fixed
value.</p>
</li>

<li>
<p>A profile shall not create new limits.</p>
</li>

<li>
<p>Any implementation that conforms to IEEE&nbsp;Std&nbsp;1003.1-2001 (including all options and extended limits required by the
profile) shall also conform to that profile.</p>
</li>
</ul>

<h5><a name="tag_02_01_05_02"></a>XSI Option Groups</h5>

<p><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
This section describes Option Groups to support the definition of XSI conformance within the System Interfaces volume of
IEEE&nbsp;Std&nbsp;1003.1-2001. This functionality is dependent on the support of the XSI extension (and the rest of this section
is not further marked). <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>

<p>The following Option Groups are defined.</p>

<h5><a name="tag_02_01_05_03"></a>Encryption</h5>

<p>The Encryption Option Group is denoted by the symbolic constant _XOPEN_CRYPT. It includes the following functions:</p>

<blockquote><a href="../functions/crypt.html"><i>crypt</i>()</a>, <a href="../functions/encrypt.html"><i>encrypt</i>()</a>, <a
href="../functions/setkey.html"><i>setkey</i>()</a></blockquote>

<p>These functions are marked CRYPT.</p>

<p>Due to export restrictions on the decoding algorithm in some countries, implementations may be restricted in making these
functions available. All the functions in the Encryption Option Group may therefore return [ENOSYS] or, alternatively, <a href=
"../functions/encrypt.html"><i>encrypt</i>()</a> shall return [ENOSYS] for the decryption operation.</p>

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

<h5><a name="tag_02_01_05_04"></a>Realtime</h5>

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

<p>This Option Group includes a set of realtime 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 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>An implementation that claims conformance to this Option Group shall set _XOPEN_REALTIME to a value other than -1.</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_ASYNCHRONOUS_IO

_POSIX_FSYNC

_POSIX_MAPPED_FILES

_POSIX_MEMLOCK