NAME

       pthread_rwlockattr_getpshared,   pthread_rwlockattr_setpshared   -   get   and   set   the
       process-shared attribute of the read-write lock attributes object

SYNOPSIS

       #include <pthread.h>

       int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *
              restrict attr, int *restrict pshared);
       int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr,
              int pshared);

DESCRIPTION

       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 associated functions  to
       get and set those attribute values are implementation-defined.

RETURN VALUE

       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.

ERRORS

       The pthread_rwlockattr_getpshared() and pthread_rwlockattr_setpshared() functions may fail
       if:

       EINVAL The value specified by attr is invalid.

       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.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       pthread_rwlock_destroy() , pthread_rwlockattr_destroy() , pthread_rwlockattr_init() ,  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 .