|PTHREAD_MUTEX_TIMEDLOCK(3P)||POSIX Programmer's Manual||PTHREAD_MUTEX_TIMEDLOCK(3P)|
#include <pthread.h> #include <time.h>
int pthread_mutex_timedlock(pthread_mutex_t *restrict mutex, const struct timespec *restrict abstime);
The timeout shall expire when the absolute time specified by abstime passes, as measured by the clock on which timeouts are based (that is, when the value of that clock equals or exceeds abstime), or if the absolute time specified by abstime has already been passed at the time of the call.
The timeout shall be based on the CLOCK_REALTIME clock. 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 abstime 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 mutex is a robust mutex and the process containing the owning thread terminated while holding the mutex lock, a call to pthread_mutex_timedlock() shall return the error value [EOWNERDEAD]. If mutex is a robust mutex and the owning thread terminated while holding the mutex lock, a call to pthread_mutex_timedlock() may return the error value [EOWNERDEAD] even if the process in which the owning thread resides has not terminated. In these cases, the mutex is locked by the thread but the state it protects is marked as inconsistent. The application should ensure that the state is made consistent for reuse and when that is complete call pthread_mutex_consistent(). If the application is unable to recover the state, it should unlock the mutex without a prior call to pthread_mutex_consistent(), after which the mutex is marked permanently unusable.
If mutex does not refer to an initialized mutex object, the behavior is undefined.
- The mutex could not be acquired because the maximum number of recursive locks for mutex has been exceeded.
- The mutex type is PTHREAD_MUTEX_ERRORCHECK and the current thread already owns the mutex.
- 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.
- The process or thread would have blocked, and the abstime parameter specified a nanoseconds field value less than zero or greater than or equal to 1000 million.
The state protected by the mutex is not recoverable.
The mutex is a robust mutex and the process containing the previous owning thread terminated while holding the mutex lock. The mutex lock shall be acquired by the calling thread and it is up to the new owner to make the state consistent.
- The mutex could not be locked before the specified timeout expired.
The pthread_mutex_timedlock() function may fail if:
- A deadlock condition was detected.
The mutex is a robust mutex and the previous owning thread terminated while holding the mutex lock. The mutex lock shall be acquired by the calling thread and it is up to the new owner to make the state consistent.
This function shall not return an error code of [EINTR].
The following sections are informative.
The Base Definitions volume of POSIX.1‐2017, Section 4.12, Memory Synchronization, <pthread.h>, <time.h>
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|2017||IEEE/The Open Group|