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