pthread_barrierattr_getpshared, pthread_barrierattr_setpshared - get and set process-shared attribute of barrier attributes object
cc –mt [ flag... ] file... [ library... ]
const pthread_barrierattr_t *restrict attr,
int *restrict pshared);
int pthread_barrierattr_setpshared(pthread_barrierattr_t *attr,
The pthread_barrierattr_getpshared() function obtains the value of the process-shared attribute from the attributes object referenced by attr. The pthread_barrierattr_setpshared() function sets 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 will 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 is PTHREAD_PROCESS_PRIVATE. Both constants PTHREAD_PROCESS_SHARED and PTHREAD_PROCESS_PRIVATE are defined in <pthread.h>.
No barrier attributes other than the process-shared attribute are provided.
Upon successful completion, the pthread_barrierattr_getpshared() function returns 0 and stores the value of the process-shared attribute of attr into the object referenced by the pshared parameter. Otherwise,
an error number is returned to indicate the error.
Upon successful completion, the pthread_barrierattr_setpshared() function returns 0. Otherwise, an error number is returned to indicate the error.
These functions may fail if:
The value specified by attr is invalid.
The pthread_barrierattr_setpshared() function may fail if:
The new value specified for the process-shared attribute is not one of the legal values PTHREAD_PROCESS_SHARED or PTHREAD_PROCESS_PRIVATE.