PROLOG

       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 .

       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.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                  PTHREAD_MUTEXATTR_GETPSHARED(3POSIX)