PTHREAD_MUTEXATTR_GETPSHARED
Section: POSIX Programmer's Manual (3P)
Updated: 2017
Page Index
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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.
NAME
pthread_mutexattr_getpshared,
pthread_mutexattr_setpshared
--- get and set the process-shared attribute
SYNOPSIS
#include <pthread.h>
int pthread_mutexattr_getpshared(const pthread_mutexattr_t
*restrict attr, int *restrict pshared);
int pthread_mutexattr_setpshared(pthread_mutexattr_t *attr,
int pshared);
DESCRIPTION
The
pthread_mutexattr_getpshared()
function shall obtain the value of the
process-shared
attribute from the attributes object referenced by
attr.
The
pthread_mutexattr_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 mutex
to be operated upon by any thread that has access to the memory where
the mutex is allocated, even if the mutex is allocated in memory that
is shared by multiple processes. 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.
The behavior is undefined if the value specified by the
attr
argument to
pthread_mutexattr_getpshared()
or
pthread_mutexattr_setpshared()
does not refer to an initialized mutex attributes object.
RETURN VALUE
Upon successful completion,
pthread_mutexattr_setpshared()
shall return zero; otherwise, an error number shall be returned to
indicate the error.
Upon successful completion,
pthread_mutexattr_getpshared()
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.
ERRORS
The
pthread_mutexattr_setpshared()
function may fail if:
- EINVAL
-
The new value specified for the attribute is outside the range of legal
values for that attribute.
These functions shall not return an error code of
[EINTR].
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
If an implementation detects that the value specified by the
attr
argument to
pthread_mutexattr_getpshared()
or
pthread_mutexattr_setpshared()
does not refer to an initialized mutex attributes object, it is
recommended that the function should fail and report an
[EINVAL]
error.
FUTURE DIRECTIONS
None.
SEE ALSO
pthread_cond_destroy(),
pthread_create(),
pthread_mutex_destroy(),
pthread_mutexattr_destroy()
The Base Definitions volume of POSIX.1-2017,
<pthread.h>
COPYRIGHT
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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