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
Additional attributes, their default values, and the names of the associated
functions to get and set those attribute values are implementation-defined.
Upon successful completion, the pthread_rwlockattr_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_rwlockattr_setpshared() function shall return
zero; otherwise, an error number shall be returned to indicate the error.
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