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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
.TH "PTHREAD_MUTEX_TIMEDLOCK" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" pthread_mutex_timedlock
.SH NAME
pthread_mutex_timedlock \- lock a mutex (\fBADVANCED REALTIME\fP)
.SH SYNOPSIS
.LP
\fB#include <pthread.h>
.br
#include <time.h>
.br
.sp
int pthread_mutex_timedlock(pthread_mutex_t *restrict\fP \fImutex\fP\fB,
.br
\ \ \ \ \ \ const struct timespec *restrict\fP \fIabs_timeout\fP\fB);
\fP
\fB
.br
\fP
.SH DESCRIPTION
.LP
The \fIpthread_mutex_timedlock\fP() function shall lock the mutex
object referenced by \fImutex\fP. If the mutex is already
locked, the calling thread shall block until the mutex becomes available
as in the \fIpthread_mutex_lock\fP() function. If the mutex cannot
be locked without waiting for
another thread to unlock the mutex, this wait shall be terminated
when the specified timeout expires.
.LP
The timeout shall expire when the absolute time specified by \fIabs_timeout\fP
passes, as measured by the clock on which
timeouts are based (that is, when the value of that clock equals or
exceeds \fIabs_timeout\fP), or if the absolute time specified
by \fIabs_timeout\fP has already been passed at the time of the call.
.LP
If the Timers option is supported, the timeout shall be based on the
CLOCK_REALTIME clock; if the Timers option is not supported,
the timeout shall be based on the system clock as returned by the
\fItime\fP() function.
.LP
The resolution of the timeout shall be the resolution of the clock
on which it is based. The \fBtimespec\fP data type is
defined in the \fI<time.h>\fP header.
.LP
Under no circumstance shall the function fail with a timeout if the
mutex can be locked immediately. The validity of the
\fIabs_timeout\fP parameter need not be checked if the mutex can be
locked immediately.
.LP
As a consequence of the priority inheritance rules (for mutexes initialized
with the PRIO_INHERIT protocol), if a timed mutex
wait is terminated because its timeout expires, the priority of the
owner of the mutex shall be adjusted as necessary to reflect
the fact that this thread is no longer among the threads waiting for
the mutex.
.SH RETURN VALUE
.LP
If successful, the \fIpthread_mutex_timedlock\fP() function shall
return zero; otherwise, an error number shall be returned to
indicate the error.
.SH ERRORS
.LP
The \fIpthread_mutex_timedlock\fP() function shall fail if:
.TP 7
.B EINVAL
The mutex was created with the protocol attribute having the value
PTHREAD_PRIO_PROTECT and the calling thread's priority is
higher than the mutex' current priority ceiling.
.TP 7
.B EINVAL
The process or thread would have blocked, and the \fIabs_timeout\fP
parameter specified a nanoseconds field value less than
zero or greater than or equal to 1000 million.
.TP 7
.B ETIMEDOUT
The mutex could not be locked before the specified timeout expired.
.sp
.LP
The \fIpthread_mutex_timedlock\fP() function may fail if:
.TP 7
.B EINVAL
The value specified by \fImutex\fP does not refer to an initialized
mutex object.
.TP 7
.B EAGAIN
The mutex could not be acquired because the maximum number of recursive
locks for \fImutex\fP has been exceeded.
.TP 7
.B EDEADLK
The current thread already owns the mutex.
.sp
.LP
This function shall not return an error code of [EINTR].
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
The \fIpthread_mutex_timedlock\fP() function is part of the Threads
and Timeouts options and need not be provided on all
implementations.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIpthread_mutex_destroy\fP() , \fIpthread_mutex_lock\fP() , \fIpthread_mutex_trylock\fP()
, \fItime\fP() , the Base Definitions volume of IEEE\ Std\ 1003.1-2001,
\fI<pthread.h>\fP, \fI<time.h>\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
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