#### POSIX Threads for Windows – REFERENCE - Pthreads-w32

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## Name

pthread_barrierattr_getpshared, pthread_barrierattr_setpshared - get and set the process-shared attribute of the barrier attributes object (ADVANCED REALTIME THREADS)

## 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>.

Pthreads-w32 defines _POSIX_THREAD_PROCESS_SHARED in pthread.h as -1 to indicate that these routines are implemented but that the process shared attribute is not supported.

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

## 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

These functions may fail if:

EINVAL
  The value specified by attr is invalid.
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.
ENOSYS
  The value specified by attr was PTHREAD_PROCESS_SHARED (Pthreads-w32).

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

The following sections are informative.

## Examples

None.

## Application Usage

The pthread_barrierattr_getpshared and pthread_barrierattr_setpshared functions are part of the Barriers option and need not be provided on all implementations.

Pthreads-w32 defines _POSIX_BARRIERS and _POSIX_THREAD_PROCESS_SHARED in pthread.h as -1 to indicate that these routines are implemented and may be used, but do not support the process shared option.

## Rationale

None.

## Future Directions

None.

## See Also

pthread_barrier_destroy(3) , pthread_barrierattr_destroy(3) , pthread_barrierattr_init(3) , the Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h>

## Copyright

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Modified by Ross Johnson for use with Pthreads-w32.

Table of Contents

- Name

- Synopsis

- Description

- Return Value

- Errors

- Examples

- Application Usage

- Rationale

- Future Directions

- See Also

- Copyright