NAME

pthread_barrierattr_getpshared, pthread_barrierattr_setpshared — get and set the process-shared attribute of the barrier attributes object

SYNOPSIS

[TSH] #include <pthread.h>

int pthread_barrierattr_getpshared(const pthread_barrierattr_t
       *restrict attr, int *restrict pshared);
int pthread_barrierattr_setpshared(pthread_barrierattr_t *attr,
       int pshared);

DESCRIPTION

The pthread_barrierattr_getpshared() function shall obtain the value of the process-shared attribute from the attributes object referenced by attr. The pthread_barrierattr_setpshared() function shall set the process-shared attribute in an initialized attributes object referenced by attr.

The process-shared attribute is set to PTHREAD_PROCESS_SHARED to permit a barrier to be operated upon by any thread that has access to the memory where the barrier is allocated. See 2.9.9 Synchronization Object Copies and Alternative Mappings for further requirements. The default value of the attribute shall be PTHREAD_PROCESS_PRIVATE. Both constants PTHREAD_PROCESS_SHARED and PTHREAD_PROCESS_PRIVATE are defined in <pthread.h>.

Additional attributes, their default values, and the names of the associated functions to get and set those attribute values are implementation-defined.

The behavior is undefined if the value specified by the attr argument to pthread_barrierattr_getpshared() or pthread_barrierattr_setpshared() does not refer to an initialized barrier attributes object.

RETURN VALUE

If successful, the pthread_barrierattr_getpshared() function shall return zero and store the value of the process-shared attribute of attr into the object referenced by the pshared parameter. Otherwise, an error number shall be returned to indicate the error.

If successful, the pthread_barrierattr_setpshared() function shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

The pthread_barrierattr_setpshared() function may fail if:

[EINVAL]

The new value specified for the process-shared attribute is not one of the legal values PTHREAD_PROCESS_SHARED or PTHREAD_PROCESS_PRIVATE.

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

EXAMPLES

None.

APPLICATION USAGE

The pthread_barrierattr_getpshared() and pthread_barrierattr_setpshared() functions are part of the Thread Process-Shared Synchronization option and need not be provided on all implementations.

RATIONALE

If an implementation detects that the value specified by the attr argument to pthread_barrierattr_getpshared() or pthread_barrierattr_setpshared() does not refer to an initialized barrier attributes object, it is recommended that the function should fail and report an [EINVAL] error.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_barrier_destroy, pthread_barrierattr_destroy

XBD <pthread.h>

CHANGE HISTORY

First released in Issue 6. Derived from IEEE Std 1003.1j-2000

Issue 7

The pthread_barrierattr_getpshared() and pthread_barrierattr_setpshared() functions are marked only as part of the Thread Process-Shared Synchronization option as the Threads option is now part of the Base.

The [EINVAL] error for an uninitialized barrier attributes object is removed; this condition results in undefined behavior.

POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0266 [972] and XSH/TC2-2008/0267 [757] are applied.