bionic (3) pthread_mutexattr_getpshared.3posix.gz

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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>


       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 .