|PTHREAD_MUTEXATTR_GETROBUST(3P)||POSIX Programmer's Manual||PTHREAD_MUTEXATTR_GETROBUST(3P)|
PROLOGThis manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAMEpthread_mutexattr_getrobust, pthread_mutexattr_setrobust — get and set the mutex robust attribute
int pthread_mutexattr_getrobust(const pthread_mutexattr_t *restrict
attr, int *restrict robust);
int pthread_mutexattr_setrobust(pthread_mutexattr_t * attr,
DESCRIPTIONThe pthread_mutexattr_getrobust() and pthread_mutexattr_setrobust() functions, respectively, shall get and set the mutex robust attribute. This attribute is set in the robust parameter. Valid values for robust include:
The behavior is undefined if the value specified by the attr argument to pthread_mutexattr_getrobust() or pthread_mutexattr_setrobust() does not refer to an initialized mutex attributes object.
RETURN VALUEUpon successful completion, the pthread_mutexattr_getrobust() function shall return zero and store the value of the robust attribute of attr into the object referenced by the robust parameter. Otherwise, an error value shall be returned to indicate the error. If successful, the pthread_mutexattr_setrobust() function shall return zero; otherwise, an error number shall be returned to indicate the error.
ERRORSThe pthread_mutexattr_setrobust() function shall fail if:
- The value of robust is invalid.
These functions shall not return an error code of [EINTR].
The following sections are informative.
APPLICATION USAGEThe actions required to make the state protected by the mutex consistent again are solely dependent on the application. If it is not possible to make the state of a mutex consistent, robust mutexes can be used to notify this situation by calling pthread_mutex_unlock() without a prior call to pthread_mutex_consistent().
If the state is declared inconsistent by calling pthread_mutex_unlock() without a prior call to pthread_mutex_consistent(), a possible approach could be to destroy the mutex and then reinitialize it. However, it should be noted that this is possible only in certain situations where the state protected by the mutex has to be reinitialized and coordination achieved with other threads blocked on the mutex, because otherwise a call to a locking function with a reference to a mutex object invalidated by a call to pthread_mutex_destroy() results in undefined behavior.
RATIONALEIf an implementation detects that the value specified by the attr argument to pthread_mutexattr_getrobust() or pthread_mutexattr_setrobust() does not refer to an initialized mutex attributes object, it is recommended that the function should fail and report an [EINVAL] error.
SEE ALSOpthread_mutex_consistent(), pthread_mutex_destroy(), pthread_mutex_lock()
The Base Definitions volume of POSIX.1‐2008, <pthread.h>
COPYRIGHTPortions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .
|2013||IEEE/The Open Group|