NAME

pthread_mutexattr_getprioceiling pthread_mutexattr_setprioceiling — get and set the prioceiling attribute of the mutex attributes object (REALTIME THREADS)

SYNOPSIS

[THR TPP]
#include <pthread.h>

int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *
       restrict attr, int *restrict prioceiling);
int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
       int prioceiling);

DESCRIPTION

The pthread_mutexattr_getprioceiling () and pthread_mutexattr_setprioceiling () functions, respectively, shall get and set the priority ceiling attribute of a mutex attributes object pointed to by attr which was previously created by the function pthread_mutexattr_init(3).

The prioceiling attribute contains the priority ceiling of initialized mutexes. The values of prioceiling are within the maximum range of priorities defined by SCHED_FIFO.

The prioceiling attribute defines the priority ceiling of initialized mutexes, which is the minimum priority level at which the critical section guarded by the mutex is executed. In order to avoid priority inversion, the priority ceiling of the mutex shall be set to a priority higher than or equal to the highest priority of all the threads that may lock that mutex. The values of prioceiling are within the maximum range of priorities defined under the SCHED_FIFO scheduling policy.

RETURN VALUE

Upon successful completion, the pthread_mutexattr_getprioceiling () and pthread_mutexattr_setprioceiling () functions shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

The pthread_mutexattr_getprioceiling () and pthread_mutexattr_setprioceiling () functions may fail if:

[EINVAL]

The value specified by attr or prioceiling is invalid.

[EPERM]

The caller does not have the privilege to perform the operation.

These functions shall not return an error code of [EINTR].

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_cond_destroy(3) , pthread_create(3) , pthread_mutex_destroy(3) , the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <pthread.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Threads Extension.

Marked as part of the Realtime Threads Feature Group.

Issue 6

The pthread_mutexattr_getprioceiling () and pthread_mutexattr_setprioceiling () functions are marked as part of the Threads and Thread Priority Protection options.

The [ENOSYS] error condition has been removed as stubs need not be provided if an implementation does not support the Thread Priority Protection option.

The [ENOTSUP] error condition has been removed since these functions do not have a protocol argument.

The restrict keyword is added to the pthread_mutexattr_getprioceiling () prototype for alignment with the ISO/IEC 9899:1999 (“ISO C99”) standard.

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