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_rwlockattr_getpshared, pthread_rwlockattr_setpshared — get and
set the process-shared attribute of the read-write lock attributes
int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t
*restrict attr, int *restrict pshared);
int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr,
The pthread_rwlockattr_getpshared() function shall obtain the value of
the process-shared attribute from the initialized attributes object
referenced by attr. The pthread_rwlockattr_setpshared() function shall
set the process-shared attribute in an initialized attributes object
referenced by attr.
The process-shared attribute shall be set to PTHREAD_PROCESS_SHARED to
permit a read-write lock to be operated upon by any thread that has
access to the memory where the read-write lock is allocated, even if
the read-write lock is allocated in memory that is shared by multiple
processes. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE,
the read-write lock shall only be operated upon by threads created
within the same process as the thread that initialized the read-write
lock; if threads of differing processes attempt to operate on such a
read-write lock, the behavior is undefined. The default value of the
process-shared attribute shall be PTHREAD_PROCESS_PRIVATE.
Additional attributes, their default values, and the names of the asso‐
ciated functions to get and set those attribute values are implementa‐
The behavior is undefined if the value specified by the attr argument
to pthread_rwlockattr_getpshared() or pthread_rwlockattr_setpshared()
does not refer to an initialized read-write lock attributes object.
Upon successful completion, the pthread_rwlockattr_getpshared() func‐
tion 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_rwlockattr_setpshared() function shall
return zero; otherwise, an error number shall be returned to indicate
The pthread_rwlockattr_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.
SEE ALSOpthread_rwlock_destroy(), pthread_rwlockattr_destroy()
The Base Definitions volume of POSIX.1‐2008, <pthread.h>
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.ker‐
IEEE/The Open Group 2013 PTHREAD_RWLOCKATTR_GETPSHARED(3P)