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authorrpj <rpj>2011-05-06 02:11:50 +0000
committerrpj <rpj>2011-05-06 02:11:50 +0000
commit2fe8aba6a8a4ce09f353f34881c77f93a9c01ca3 (patch)
treefd7f179b1abaa525ec55e34bef23b12f8fd89021 /manual/pthread_mutex_init.html
parent941d7cf87c60b55342b51e0b0fcd748589b76167 (diff)
Robust mutexes merged from devel branchpost_merge_with_ROBUST_MUTEXES
Diffstat (limited to 'manual/pthread_mutex_init.html')
-rw-r--r--manual/pthread_mutex_init.html225
1 files changed, 152 insertions, 73 deletions
diff --git a/manual/pthread_mutex_init.html b/manual/pthread_mutex_init.html
index f9982cf..cdb333e 100644
--- a/manual/pthread_mutex_init.html
+++ b/manual/pthread_mutex_init.html
@@ -3,22 +3,37 @@
<HEAD>
<META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=utf-8">
<TITLE>PTHREAD_MUTEX(3) manual page</TITLE>
- <META NAME="GENERATOR" CONTENT="OpenOffice.org 1.1.3 (Linux)">
+ <META NAME="GENERATOR" CONTENT="OpenOffice.org 3.2 (Linux)">
<META NAME="CREATED" CONTENT="20050505;5000">
- <META NAME="CHANGED" CONTENT="20050505;19000600">
+ <META NAME="CHANGEDBY" CONTENT="Ross Johnson">
+ <META NAME="CHANGED" CONTENT="20110326;15072100">
+ <META NAME="CHANGEDBY" CONTENT="Ross Johnson">
+ <META NAME="CHANGEDBY" CONTENT="Ross Johnson">
<!-- manual page source format generated by PolyglotMan v3.2, -->
<!-- available at http://polyglotman.sourceforge.net/ -->
+ <STYLE TYPE="text/css">
+ <!--
+ H4.cjk { font-family: "AR PL UMing CN" }
+ H4.ctl { font-family: "Lohit Devanagari" }
+ H2.cjk { font-family: "AR PL UMing CN" }
+ H2.ctl { font-family: "Lohit Devanagari" }
+ PRE.cjk { font-family: "AR PL UMing CN", monospace }
+ PRE.ctl { font-family: "Lohit Devanagari", monospace }
+ -->
+ </STYLE>
</HEAD>
<BODY LANG="en-GB" BGCOLOR="#ffffff" DIR="LTR">
-<H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4>
+<H4 CLASS="western">POSIX Threads for Windows – REFERENCE -
+<A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4>
<P><A HREF="index.html">Reference Index</A></P>
<P><A HREF="#toc">Table of Contents</A></P>
-<H2><A HREF="#toc0" NAME="sect0">Name</A></H2>
+<H2 CLASS="western"><A HREF="#toc0" NAME="sect0">Name</A></H2>
<P>pthread_mutex_init, pthread_mutex_lock, pthread_mutex_trylock,
-pthread_mutex_timedlock, pthread_mutex_unlock, pthread_mutex_destroy
-- operations on mutexes
+pthread_mutex_timedlock, pthread_mutex_unlock,
+pthread_mutex_consistent, pthread_mutex_destroy - operations on
+mutexes
</P>
-<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2>
+<H2 CLASS="western"><A HREF="#toc1" NAME="sect1">Synopsis</A></H2>
<P><B>#include &lt;pthread.h&gt;</B>
</P>
<P><B>#include &lt;time.h&gt;</B></P>
@@ -49,9 +64,11 @@ const pthread_mutexattr_t *</B><I>mutexattr</I><B>);</B>
</P>
<P><B>int pthread_mutex_unlock(pthread_mutex_t *</B><I>mutex</I><B>);</B>
</P>
+<P><B>int pthread_mutex_consistent(pthread_mutex_t *</B><I>mutex</I><B>);</B>
+</P>
<P><B>int pthread_mutex_destroy(pthread_mutex_t *</B><I>mutex</I><B>);</B>
</P>
-<H2><A HREF="#toc2" NAME="sect2">Description</A></H2>
+<H2 CLASS="western"><A HREF="#toc2" NAME="sect2">Description</A></H2>
<P>A mutex is a MUTual EXclusion device, and is useful for protecting
shared data structures from concurrent modifications, and
implementing critical sections and monitors.
@@ -76,16 +93,22 @@ for more information on mutex attributes.
statically, using the constants <B>PTHREAD_MUTEX_INITIALIZER</B> (for
normal “fast” mutexes), <B>PTHREAD_RECURSIVE_MUTEX_INITIALIZER</B>
(for recursive mutexes), and <B>PTHREAD_ERRORCHECK_MUTEX_INITIALIZER</B>
-(for error checking mutexes). <SPAN STYLE="font-weight: medium"> In
-the <B>Pthreads-w32</B> implementation, an application should still
-call <B>pthread_mutex_destroy</B> at some point to ensure that any
+(for error checking mutexes). <SPAN STYLE="font-weight: normal">In
+the </SPAN><B>Pthreads-w32</B> <SPAN STYLE="font-weight: normal">implementation,
+an application should still call </SPAN><B>pthread_mutex_destroy</B>
+<SPAN STYLE="font-weight: normal">at some point to ensure that any
resources consumed by the mutex are released.</SPAN></P>
+<P><SPAN STYLE="font-weight: normal">Any mutex type can be
+initialized as a </SPAN><B>robust mutex</B><SPAN STYLE="font-weight: normal">.
+See </SPAN><A HREF="pthread_mutexattr_init.html"><B>pthread_mutexattr_init</B><SPAN STYLE="font-weight: normal">(3)</SPAN></A>
+<SPAN STYLE="font-weight: normal">for more information as well as the
+section </SPAN><I><U><SPAN STYLE="font-weight: normal">Robust Mutexes</SPAN></U></I>
+<SPAN STYLE="font-weight: normal">below.</SPAN></P>
<P><B>pthread_mutex_lock</B> locks the given mutex. If the mutex is
currently unlocked, it becomes locked and owned by the calling
thread, and <B>pthread_mutex_lock</B> returns immediately. If the
mutex is already locked by another thread, <B>pthread_mutex_lock</B>
-suspends the calling thread until the mutex is unlocked.
-</P>
+suspends the calling thread until the mutex is unlocked.</P>
<P>If the mutex is already locked by the calling thread, the behavior
of <B>pthread_mutex_lock</B> depends on the type of the mutex. If the
mutex is of the “normal” type, the calling thread is suspended
@@ -101,15 +124,18 @@ be performed before the mutex returns to the unlocked state.
<P><B>pthread_mutex_trylock</B> behaves identically to
<B>pthread_mutex_lock</B>, except that it does not block the calling
thread if the mutex is already locked by another thread (or by the
-calling thread in the case of a “normal” mutex). Instead,
-<B>pthread_mutex_trylock</B> returns immediately with the error code
-<B>EBUSY</B>.
+calling thread in the case of a “normal” or “<SPAN STYLE="font-style: normal">errorcheck</SPAN>”
+mutex). Instead, <B>pthread_mutex_trylock</B> returns immediately
+with the error code <B>EBUSY</B>.
</P>
<P><B>pthread_mutex_timedlock</B> behaves identically to
<B>pthread_mutex_lock</B>, except that if it cannot acquire the lock
before the <I>abs_timeout</I> time, the call returns with the error
code <B>ETIMEDOUT</B>. If the mutex can be locked immediately it is,
and the <B>abs_timeout</B> parameter is ignored.</P>
+<P><B>pthread_mutex_consistent</B> may only be called for
+<B>PTHREAD_MUTEX_ROBUST</B> mutexes. It simply marks the mutex as
+consistent. See <I><U>Robust Mutexes</U></I> below.</P>
<P><B>pthread_mutex_unlock</B> unlocks the given mutex. The mutex is
assumed to be locked and owned by the calling thread on entrance to
<B>pthread_mutex_unlock</B>. If the mutex is of the “normal”
@@ -117,19 +143,53 @@ type, <B>pthread_mutex_unlock</B> always returns it to the unlocked
state. If it is of the ‘‘recursive’’ type, it decrements the
locking count of the mutex (number of <B>pthread_mutex_lock</B>
operations performed on it by the calling thread), and only when this
-count reaches zero is the mutex actually unlocked.
-</P>
+count reaches zero is the mutex actually unlocked. In <B>Pthreads-win32</B>,
+non-robust normal or default mutex types do not check the owner of
+the mutex. For all types of robust mutexes the owner is checked and
+an error code is returned if the calling thread does not own the
+mutex.</P>
<P>On ‘‘error checking’’ mutexes, <B>pthread_mutex_unlock</B>
actually checks at run-time that the mutex is locked on entrance, and
that it was locked by the same thread that is now calling
<B>pthread_mutex_unlock</B>. If these conditions are not met, an
error code is returned and the mutex remains unchanged. ‘‘Normal’’
-mutexes perform no such checks, thus allowing a locked mutex to be
-unlocked by a thread other than its owner. This is non-portable
-behavior and is not meant to be used as a feature.</P>
+[non-robust] mutexes perform no such checks, thus allowing a locked
+mutex to be unlocked by a thread other than its owner. This is
+non-portable behavior and is not meant to be used as a feature.</P>
<P><B>pthread_mutex_destroy</B> destroys a mutex object, freeing the
resources it might hold. The mutex must be unlocked on entrance.</P>
-<H2><A HREF="#toc3" NAME="sect3">Cancellation</A></H2>
+<H2 CLASS="western"><A HREF="#toc10" NAME="sect10">Robust Mutexes</A></H2>
+<P>If the mutex is <B>PTHREAD_MUTEX_ROBUST</B> and the owning thread
+terminates without unlocking the mutex the implementation will wake
+one waiting thread, if any. The next thread to acquire the mutex will
+receive the error code <B>EOWNERDEAD</B><SPAN STYLE="font-weight: normal">,
+in which case that thread should if possible ensure that the state
+protected by the mutex is consistent and then call
+</SPAN><B>pthread_mutex_consistent</B> <SPAN STYLE="font-weight: normal">before
+unlocking. The mutex may then be used normally from then on.</SPAN></P>
+<P><SPAN STYLE="font-weight: normal">If the thread cannot recover the
+state then it must call </SPAN><B>pthread_mutex_unlock</B><SPAN STYLE="font-weight: normal">
+without calling </SPAN><B>pthread_mutex_consistent</B><SPAN STYLE="font-weight: normal">.
+This will mark the mutex as unusable and wake all currently waiting
+threads with the return code </SPAN><B>ENOTRECOVERABLE</B><SPAN STYLE="font-weight: normal">.
+The error indicates that the mutex is no longer usable and any
+threads that receive this error code from any lock operation have not
+acquired the mutex. The mutex can be made consistent by calling
+</SPAN><B>pthread_mutex_destroy</B> <SPAN STYLE="font-weight: normal">to
+uninitialize the mutex, and calling </SPAN><B>pthread_mutex_int</B>
+<SPAN STYLE="font-weight: normal">to reinitialize the mutex. However,
+the state that was protected by the mutex remains inconsistent and
+some form of application recovery is required.</SPAN></P>
+<P><SPAN STYLE="font-weight: normal">If a thread that receives the
+</SPAN><B>EOWNERDEAD</B> <SPAN STYLE="font-weight: normal">error code
+itself terminates without unlocking the mutex then this behaviour
+repeats for the next acquiring thread.</SPAN></P>
+<P><SPAN STYLE="font-weight: normal">Applications must ensure that
+they check the return values from all calls targeting robust mutexes.</SPAN></P>
+<P STYLE="font-weight: normal">Robust mutexes are slower because they
+require some additional overhead, however they are not very much
+slower than the non-robust recursive type.</P>
+<H2 CLASS="western"><A HREF="#toc3" NAME="sect3">Cancellation</A></H2>
<P>None of the mutex functions is a cancellation point, not even
<B>pthread_mutex_lock</B>, in spite of the fact that it can suspend a
thread for arbitrary durations. This way, the status of mutexes at
@@ -138,46 +198,56 @@ unlock precisely those mutexes that need to be unlocked before the
thread stops executing. Consequently, threads using deferred
cancellation should never hold a mutex for extended periods of time.
</P>
-<H2><A HREF="#toc4" NAME="sect4">Async-signal Safety</A></H2>
+<H2 CLASS="western"><A HREF="#toc4" NAME="sect4">Async-signal Safety</A></H2>
<P>The mutex functions are not async-signal safe. What this means is
that they should not be called from a signal handler. In particular,
calling <B>pthread_mutex_lock</B> or <B>pthread_mutex_unlock</B> from
a signal handler may deadlock the calling thread.
</P>
-<H2><A HREF="#toc5" NAME="sect5">Return Value</A></H2>
+<H2 CLASS="western"><A HREF="#toc5" NAME="sect5">Return Value</A></H2>
<P><B>pthread_mutex_init</B> always returns 0. The other mutex
functions return 0 on success and a non-zero error code on error.
</P>
-<H2><A HREF="#toc6" NAME="sect6">Errors</A></H2>
+<H2 CLASS="western"><A HREF="#toc6" NAME="sect6">Errors</A></H2>
<P>The <B>pthread_mutex_lock</B> function returns the following error
code on error:
</P>
<DL>
<DL>
- <DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ <DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in"><B>EINVAL</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex has not been properly initialized.
- </DD><DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
- <B>EDEADLK</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>EDEADLK</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex is already locked by the calling thread (‘‘error
checking’’ mutexes only).
- </DD></DL>
-</DL>
-<P>
-The <B>pthread_mutex_trylock</B> function returns the following error
-codes on error:
-</P>
-<DL>
- <DL>
- <DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EBUSY</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>EOWNERDEAD</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ the robust mutex is now locked by the calling thread after the
+ previous owner terminated without unlocking it.</DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>ENOTRECOVERABLE</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ the robust mutex is not locked and is no longer usable after the
+ previous owner unlocked it without calling
+ pthread_mutex_consistent.</DD></DL>
+ <DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ The <B>pthread_mutex_trylock</B> function returns the following
+ error codes on error:
+ </DD><DL>
+ <DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>EBUSY</B>
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex could not be acquired because it was currently locked.
- </DD><DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
<B>EINVAL</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex has not been properly initialized.
- </DD></DL>
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>EOWNERDEAD</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ the robust mutex is now locked by the calling thread after the
+ previous owner terminated without unlocking it.</DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>ENOTRECOVERABLE</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ the robust mutex is not locked and is no longer usable after the
+ previous owner unlocked it without calling
+ pthread_mutex_consistent.</DD></DL>
</DL>
<P>
The <B>pthread_mutex_timedlock</B> function returns the following
@@ -185,15 +255,22 @@ error codes on error:
</P>
<DL>
<DL>
- <DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>ETIMEDOUT</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ <DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in"><B>ETIMEDOUT</B>
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex could not be acquired before the <I>abs_timeout</I> time
arrived.
- </DD><DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
<B>EINVAL</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex has not been properly initialized.
- </DD></DL>
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>EOWNERDEAD</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ the robust mutex is now locked by the calling thread after the
+ previous owner terminated without unlocking it.</DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ <B>ENOTRECOVERABLE</B></DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
+ the robust mutex is not locked and is no longer usable after the
+ previous owner unlocked it without calling
+ pthread_mutex_consistent.</DD></DL>
</DL>
<P>
The <B>pthread_mutex_unlock</B> function returns the following error
@@ -201,12 +278,12 @@ code on error:
</P>
<DL>
<DL>
- <DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ <DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in"><B>EINVAL</B>
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex has not been properly initialized.
- </DD><DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DD><DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
<B>EPERM</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the calling thread does not own the mutex (‘‘error checking’’
mutexes only).
</DD></DL>
@@ -217,61 +294,63 @@ code on error:
</P>
<DL>
<DL>
- <DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EBUSY</B>
- </DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm">
+ <DT STYLE="margin-right: 0.39in; margin-bottom: 0.2in"><B>EBUSY</B>
+ </DT><DD STYLE="margin-right: 0.39in; margin-bottom: 0.2in">
the mutex is currently locked.
</DD></DL>
</DL>
-<H2>
+<H2 CLASS="western">
<A HREF="#toc7" NAME="sect7">Author</A></H2>
<P>Xavier Leroy &lt;Xavier.Leroy@inria.fr&gt;
</P>
<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P>
-<H2><A HREF="#toc8" NAME="sect8">See Also</A></H2>
+<H2 CLASS="western"><A HREF="#toc8" NAME="sect8">See Also</A></H2>
<P><A HREF="pthread_mutexattr_init.html"><B>pthread_mutexattr_init</B>(3)</A>
, <A HREF="pthread_mutexattr_init.html"><B>pthread_mutexattr_settype</B>(3)</A>
, <A HREF="pthread_cancel.html"><B>pthread_cancel</B>(3)</A> .
</P>
-<H2><A HREF="#toc9" NAME="sect9">Example</A></H2>
+<H2 CLASS="western"><A HREF="#toc9" NAME="sect9">Example</A></H2>
<P>A shared global variable <I>x</I> can be protected by a mutex as
follows:
</P>
-<PRE STYLE="margin-left: 1cm; margin-right: 1cm">int x;
-pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;</PRE><BLOCKQUOTE STYLE="margin-left: 0cm; margin-right: 0cm">
+<PRE CLASS="western" STYLE="margin-left: 0.39in; margin-right: 0.39in">int x;
+pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;</PRE><BLOCKQUOTE STYLE="margin-left: 0in; margin-right: 0in">
All accesses and modifications to <I>x</I> should be bracketed by
calls to <B>pthread_mutex_lock</B> and <B>pthread_mutex_unlock</B> as
follows:
</BLOCKQUOTE>
-<PRE STYLE="margin-left: 1.03cm; margin-right: 2cm">pthread_mutex_lock(&amp;mut);
+<PRE CLASS="western" STYLE="margin-left: 0.41in; margin-right: 0.79in">pthread_mutex_lock(&amp;mut);
/* operate on x */
pthread_mutex_unlock(&amp;mut);</PRE>
<HR>
-<BLOCKQUOTE STYLE="margin-right: 4cm"><A NAME="toc"></A><B>Table of
-Contents</B></BLOCKQUOTE>
+<BLOCKQUOTE STYLE="margin-right: 2.75in"><A NAME="toc"></A><B>Table
+of Contents</B></BLOCKQUOTE>
<UL>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect0" NAME="toc0">Name</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect1" NAME="toc1">Synopsis</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect2" NAME="toc2">Description</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">Cancellation</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect10" NAME="toc10">Robust
+ Mutexes</A></BLOCKQUOTE>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect3" NAME="toc3">Cancellation</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">Async-signal
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect4" NAME="toc4">Async-signal
Safety</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">Return
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect5" NAME="toc5">Return
Value</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">Errors</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect6" NAME="toc6">Errors</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">Author</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect7" NAME="toc7">Author</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm; margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">See
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in; margin-bottom: 0in"><A HREF="#sect8" NAME="toc8">See
Also</A>
</BLOCKQUOTE>
- <LI><BLOCKQUOTE STYLE="margin-right: 4cm"><A HREF="#sect9" NAME="toc9">Example</A>
+ <LI><BLOCKQUOTE STYLE="margin-right: 2.75in"><A HREF="#sect9" NAME="toc9">Example</A>
</BLOCKQUOTE>
</UL>
</BODY>
-</HTML>
+</HTML> \ No newline at end of file