PTHREAD_RWLOCKATTR_GETPSHARPOSIX Programmer's PTHREAD_RWLOCKATTR_GETPSHARED(P)



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 asso-
       ciated  functions to get and set those attribute values are implementa-
       tion-defined.

RETURN VALUE
       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 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 .



IEEE/The Open Group                  2003     PTHREAD_RWLOCKATTR_GETPSHARED(P)