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. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE, the barrier shall only be operated upon by threads created within the same process as the thread that initialized the barrier; if threads of different processes attempt to operate on such a barrier, the behavior is undefined. 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 moved from the Barriers option.

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