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.
#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);
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 Section 2.9.9, Synchronization Object Copies and Alternative Mappings 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.
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.
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.
These functions shall not return an error code of [EINTR].
The following sections are informative.
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.
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.
The Base Definitions volume of POSIX.1-2017, <pthread.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .
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