pthread_barrierattr_getpshared man page

Prolog

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

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

Synopsis

#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].

The following sections are informative.

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.

See Also

pthread_barrier_destroy(), pthread_barrierattr_destroy()

The Base Definitions volume of POSIX.1‐2008, <pthread.h>

Info

2013 IEEE/The Open Group POSIX Programmer's Manual