NAME
pthread_barrierattr_getpshared
pthread_barrierattr_setpshared —
get and set the process-shared attribute of the barrier
attributes object
SYNOPSIS
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 V2_chap02(3) 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(3), pthread_barrierattr_destroy(3)
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.