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<H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4>
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<P><A HREF="index.html">Reference Index</A></P>
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<P><A HREF="#toc">Table of Contents</A></P>
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<H2><A HREF="#toc0" NAME="sect0">Name</A></H2>
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<P>pthread_rwlockattr_getpshared, pthread_rwlockattr_setpshared - get
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and set the process-shared attribute of the read-write lock
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<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2>
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<P><B>#include <pthread.h> </B>
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<P><B>int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *
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restrict </B><I>attr</I><B>, int *restrict</B> <I>pshared</I><B>);
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<BR>int pthread_rwlockattr_setpshared(pthread_rwlockattr_t <I>*</I></B><I>attr</I><B>,
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int</B> <I>pshared</I><B>); </B>
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<H2><A HREF="#toc2" NAME="sect2">Description</A></H2>
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<P>The <B>pthread_rwlockattr_getpshared</B> function shall obtain the
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value of the <I>process-shared</I> attribute from the initialized
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attributes object referenced by <I>attr</I>. The
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<B>pthread_rwlockattr_setpshared</B> function shall set the
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<I>process-shared</I> attribute in an initialized attributes object
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referenced by <I>attr</I>.
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<P>The <I>process-shared</I> attribute shall be set to
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<B>PTHREAD_PROCESS_SHARED</B> to permit a read-write lock to be
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operated upon by any thread that has access to the memory where the
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read-write lock is allocated, even if the read-write lock is
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allocated in memory that is shared by multiple processes. If the
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<I>process-shared</I> attribute is <B>PTHREAD_PROCESS_PRIVATE</B>,
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the read-write lock shall only be operated upon by threads created
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within the same process as the thread that initialized the read-write
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lock; if threads of differing processes attempt to operate on such a
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read-write lock, the behavior is undefined. The default value of the
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<I>process-shared</I> attribute shall be <B>PTHREAD_PROCESS_PRIVATE</B>.
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<P><B>Pthreads-w32</B> defines <B>_POSIX_THREAD_PROCESS_SHARED</B> in
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pthread.h as -1 to indicate that these routines are implemented but
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they do not support the process shared option.</P>
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<P>Additional attributes, their default values, and the names of the
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associated functions to get and set those attribute values are
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implementation-defined.
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<P><B>Pthreads-w32</B> defines <B>_POSIX_READER_WRITER_LOCKS</B> in
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pthread.h as 200112L to indicate that the reader/writer routines are
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implemented and may be used.</P>
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<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2>
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<P>Upon successful completion, the <B>pthread_rwlockattr_getpshared</B>
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function shall return zero and store the value of the <I>process-shared</I>
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attribute of <I>attr</I> into the object referenced by the <I>pshared</I>
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parameter. Otherwise, an error number shall be returned to indicate
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<P>If successful, the <B>pthread_rwlockattr_setpshared</B> function
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shall return zero; otherwise, an error number shall be returned to
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<H2><A HREF="#toc4" NAME="sect4">Errors</A></H2>
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<P>The <B>pthread_rwlockattr_getpshared</B> and
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<B>pthread_rwlockattr_setpshared</B> functions may fail if:
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</DT><DD STYLE="margin-bottom: 0.5cm">
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The value specified by <I>attr</I> is invalid.
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The <B>pthread_rwlockattr_setpshared</B> function may fail if:
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</DT><DD STYLE="margin-bottom: 0.5cm">
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The new value specified for the attribute is outside the range of
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legal values for that attribute.
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</DT><DD STYLE="margin-bottom: 0.5cm">
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The new value specified for the attribute is <B>PTHREAD_PROCESS_SHARED</B>.
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These functions shall not return an error code of [EINTR].
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<P><I>The following sections are informative.</I>
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<H2><A HREF="#toc5" NAME="sect5">Examples</A></H2>
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<H2><A HREF="#toc6" NAME="sect6">Application Usage</A></H2>
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<H2><A HREF="#toc7" NAME="sect7">Rationale</A></H2>
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<H2><A HREF="#toc8" NAME="sect8">Future Directions</A></H2>
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<H2><A HREF="#toc9" NAME="sect9">See Also</A></H2>
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<P><A HREF="pthread_rwlock_init.html"><B>pthread_rwlock_destroy</B>(3)</A>
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<B>,</B> <A HREF="pthread_rwlockattr_init.html"><B>pthread_rwlockattr_destroy</B>(3)</A>
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<B>,</B> <A HREF="pthread_rwlockattr_init.html"><B>pthread_rwlockattr_init</B>(3)</A>
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<B>,</B> the Base Definitions volume of IEEE Std 1003.1-2001,
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<I><pthread.h></I>
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<H2><A HREF="#toc10" NAME="sect10">Copyright</A></H2>
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<P>Portions of this text are reprinted and reproduced in electronic
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form from IEEE Std 1003.1, 2003 Edition, Standard for Information
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Technology -- Portable Operating System Interface (POSIX), The Open
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Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the
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Institute of Electrical and Electronics Engineers, Inc and The Open
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Group. In the event of any discrepancy between this version and the
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original IEEE and The Open Group Standard, the original IEEE and The
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Open Group Standard is the referee document. The original Standard
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can be obtained online at <A HREF="http://www.opengroup.org/unix/online.html">http://www.opengroup.org/unix/online.html</A>
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<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P>
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<P><A NAME="toc"></A><B>Table of Contents</B></P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">Return
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">Errors</A>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">Examples</A>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">Application
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">Rationale</A>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">Future
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect9" NAME="toc9">See
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<LI><P><A HREF="#sect10" NAME="toc10">Copyright</A>