pthread_rwlockattr_setpshared.html 6.7 KB

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  5. <TITLE>&quot;PTHREAD_RWLOCKATTR_GETPSHARED&quot;(P) manual page</TITLE>
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  13. <H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4>
  14. <P><A HREF="index.html">Reference Index</A></P>
  15. <P><A HREF="#toc">Table of Contents</A></P>
  16. <H2><A HREF="#toc0" NAME="sect0">Name</A></H2>
  17. <P>pthread_rwlockattr_getpshared, pthread_rwlockattr_setpshared - get
  18. and set the process-shared attribute of the read-write lock
  19. attributes object
  20. </P>
  21. <H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2>
  22. <P><B>#include &lt;pthread.h&gt; </B>
  23. </P>
  24. <P><B>int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *
  25. restrict </B><I>attr</I><B>, int *restrict</B> <I>pshared</I><B>);
  26. <BR>int pthread_rwlockattr_setpshared(pthread_rwlockattr_t <I>*</I></B><I>attr</I><B>,
  27. int</B> <I>pshared</I><B>); </B>
  28. </P>
  29. <H2><A HREF="#toc2" NAME="sect2">Description</A></H2>
  30. <P>The <B>pthread_rwlockattr_getpshared</B> function shall obtain the
  31. value of the <I>process-shared</I> attribute from the initialized
  32. attributes object referenced by <I>attr</I>. The
  33. <B>pthread_rwlockattr_setpshared</B> function shall set the
  34. <I>process-shared</I> attribute in an initialized attributes object
  35. referenced by <I>attr</I>.
  36. </P>
  37. <P>The <I>process-shared</I> attribute shall be set to
  38. <B>PTHREAD_PROCESS_SHARED</B> to permit a read-write lock to be
  39. operated upon by any thread that has access to the memory where the
  40. read-write lock is allocated, even if the read-write lock is
  41. allocated in memory that is shared by multiple processes. If the
  42. <I>process-shared</I> attribute is <B>PTHREAD_PROCESS_PRIVATE</B>,
  43. the read-write lock shall only be operated upon by threads created
  44. within the same process as the thread that initialized the read-write
  45. lock; if threads of differing processes attempt to operate on such a
  46. read-write lock, the behavior is undefined. The default value of the
  47. <I>process-shared</I> attribute shall be <B>PTHREAD_PROCESS_PRIVATE</B>.
  48. </P>
  49. <P><B>Pthreads-w32</B> defines <B>_POSIX_THREAD_PROCESS_SHARED</B> in
  50. pthread.h as -1 to indicate that these routines are implemented but
  51. they do not support the process shared option.</P>
  52. <P>Additional attributes, their default values, and the names of the
  53. associated functions to get and set those attribute values are
  54. implementation-defined.
  55. </P>
  56. <P><B>Pthreads-w32</B> defines <B>_POSIX_READER_WRITER_LOCKS</B> in
  57. pthread.h as 200112L to indicate that the reader/writer routines are
  58. implemented and may be used.</P>
  59. <H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2>
  60. <P>Upon successful completion, the <B>pthread_rwlockattr_getpshared</B>
  61. function shall return zero and store the value of the <I>process-shared</I>
  62. attribute of <I>attr</I> into the object referenced by the <I>pshared</I>
  63. parameter. Otherwise, an error number shall be returned to indicate
  64. the error.
  65. </P>
  66. <P>If successful, the <B>pthread_rwlockattr_setpshared</B> function
  67. shall return zero; otherwise, an error number shall be returned to
  68. indicate the error.
  69. </P>
  70. <H2><A HREF="#toc4" NAME="sect4">Errors</A></H2>
  71. <P>The <B>pthread_rwlockattr_getpshared</B> and
  72. <B>pthread_rwlockattr_setpshared</B> functions may fail if:
  73. </P>
  74. <DL>
  75. <DT><B>EINVAL</B>
  76. </DT><DD STYLE="margin-bottom: 0.5cm">
  77. The value specified by <I>attr</I> is invalid.
  78. </DD></DL>
  79. <P>
  80. The <B>pthread_rwlockattr_setpshared</B> function may fail if:
  81. </P>
  82. <DL>
  83. <DT><B>EINVAL</B>
  84. </DT><DD STYLE="margin-bottom: 0.5cm">
  85. The new value specified for the attribute is outside the range of
  86. legal values for that attribute.
  87. </DD><DT>
  88. <B>ENOTSUP</B>
  89. </DT><DD STYLE="margin-bottom: 0.5cm">
  90. The new value specified for the attribute is <B>PTHREAD_PROCESS_SHARED</B>.
  91. </DD></DL>
  92. <P>
  93. These functions shall not return an error code of [EINTR].
  94. </P>
  95. <P><I>The following sections are informative.</I>
  96. </P>
  97. <H2><A HREF="#toc5" NAME="sect5">Examples</A></H2>
  98. <P>None.
  99. </P>
  100. <H2><A HREF="#toc6" NAME="sect6">Application Usage</A></H2>
  101. <P>None.
  102. </P>
  103. <H2><A HREF="#toc7" NAME="sect7">Rationale</A></H2>
  104. <P>None.
  105. </P>
  106. <H2><A HREF="#toc8" NAME="sect8">Future Directions</A></H2>
  107. <P>None.
  108. </P>
  109. <H2><A HREF="#toc9" NAME="sect9">See Also</A></H2>
  110. <P><A HREF="pthread_rwlock_init.html"><B>pthread_rwlock_destroy</B>(3)</A>
  111. <B>,</B> <A HREF="pthread_rwlockattr_init.html"><B>pthread_rwlockattr_destroy</B>(3)</A>
  112. <B>,</B> <A HREF="pthread_rwlockattr_init.html"><B>pthread_rwlockattr_init</B>(3)</A>
  113. <B>,</B> the Base Definitions volume of IEEE&nbsp;Std&nbsp;1003.1-2001,
  114. <I>&lt;pthread.h&gt;</I>
  115. </P>
  116. <H2><A HREF="#toc10" NAME="sect10">Copyright</A></H2>
  117. <P>Portions of this text are reprinted and reproduced in electronic
  118. form from IEEE Std 1003.1, 2003 Edition, Standard for Information
  119. Technology -- Portable Operating System Interface (POSIX), The Open
  120. Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the
  121. Institute of Electrical and Electronics Engineers, Inc and The Open
  122. Group. In the event of any discrepancy between this version and the
  123. original IEEE and The Open Group Standard, the original IEEE and The
  124. Open Group Standard is the referee document. The original Standard
  125. can be obtained online at <A HREF="http://www.opengroup.org/unix/online.html">http://www.opengroup.org/unix/online.html</A>
  126. .
  127. </P>
  128. <P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P>
  129. <HR>
  130. <P><A NAME="toc"></A><B>Table of Contents</B></P>
  131. <UL>
  132. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A>
  133. </P>
  134. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A>
  135. </P>
  136. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A>
  137. </P>
  138. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">Return
  139. Value</A>
  140. </P>
  141. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">Errors</A>
  142. </P>
  143. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">Examples</A>
  144. </P>
  145. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">Application
  146. Usage</A>
  147. </P>
  148. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">Rationale</A>
  149. </P>
  150. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">Future
  151. Directions</A>
  152. </P>
  153. <LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect9" NAME="toc9">See
  154. Also</A>
  155. </P>
  156. <LI><P><A HREF="#sect10" NAME="toc10">Copyright</A>
  157. </P>
  158. </UL>
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