Originální popis anglicky:
pthread_mutex_timedlock - lock a mutex (
ADVANCED REALTIME)
Návod, kniha: POSIX Programmer's Manual
#include <pthread.h>
#include <time.h>
int pthread_mutex_timedlock(pthread_mutex_t *restrict
mutex ,
const struct timespec *restrict
abs_timeout);
The
pthread_mutex_timedlock() function shall lock the mutex object
referenced by
mutex. If the mutex is already locked, the calling thread
shall block until the mutex becomes available as in the
pthread_mutex_lock() 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.
The timeout shall expire when the absolute time specified by
abs_timeout
passes, as measured by the clock on which timeouts are based (that is, when
the value of that clock equals or exceeds
abs_timeout), or if the
absolute time specified by
abs_timeout has already been passed at the
time of the call.
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
time() function.
The resolution of the timeout shall be the resolution of the clock on which it
is based. The
timespec data type is defined in the
<time.h> header.
Under no circumstance shall the function fail with a timeout if the mutex can be
locked immediately. The validity of the
abs_timeout parameter need not
be checked if the mutex can be locked immediately.
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.
If successful, the
pthread_mutex_timedlock() function shall return zero;
otherwise, an error number shall be returned to indicate the error.
The
pthread_mutex_timedlock() function shall fail if:
- 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.
- EINVAL
- The process or thread would have blocked, and the
abs_timeout parameter specified a nanoseconds field value less than
zero or greater than or equal to 1000 million.
- ETIMEDOUT
- The mutex could not be locked before the specified timeout
expired.
The
pthread_mutex_timedlock() function may fail if:
- EINVAL
- The value specified by mutex does not refer to an
initialized mutex object.
- EAGAIN
- The mutex could not be acquired because the maximum number
of recursive locks for mutex has been exceeded.
- EDEADLK
- The current thread already owns the mutex.
This function shall not return an error code of [EINTR].
The following sections are informative.
None.
The
pthread_mutex_timedlock() function is part of the Threads and
Timeouts options and need not be provided on all implementations.
None.
None.
pthread_mutex_destroy() ,
pthread_mutex_lock() ,
pthread_mutex_trylock() ,
time() , the Base Definitions volume
of IEEE Std 1003.1-2001,
<pthread.h>,
<time.h>
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
.
