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.  If  the
       process-shared attribute is PTHREAD_PROCESS_PRIVATE, the mutex shall only be operated upon
       by threads created within the same process as the thread that initialized  the  mutex;  if
       threads  of  differing  processes  attempt  to  operate  on  such a mutex, the behavior is
       undefined. 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.1‐2008, <pthread.h>

COPYRIGHT

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