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PTHREAD_MUTEXATTR_GETPSHARELinux Programmer's MPTHREAD_MUTEXATTR_GETPSHARED(3)

NAME

     pthread_mutexattr_getpshared,  pthread_mutexattr_setpshared  -  get/set
     process-shared mutex attribute

SYNOPSIS

     #include <pthread.h>

     int pthread_mutexattr_getpshared(const pthread_mutexattr_t *attr,
                                      int *pshared);
     int pthread_mutexattr_setpshared(pthread_mutexattr_t *attr,
                                      int pshared);

     Compile and link with -pthread.

DESCRIPTION

     These functions get and set the process-shared  attribute  in  a  mutex
     attributes  object.  This attribute must be appropriately set to ensure
     correct, efficient operation of a mutex created using  this  attributes
     object.

     The process-shared attribute can have one of the following values:

     PTHREAD_PROCESS_PRIVATE
            Mutexes  created  with  this  attributes object are to be shared
            only among threads in the  same  process  that  initialized  the
            mutex.   This  is the default value for the process-shared mutex
            attribute.

     PTHREAD_PROCESS_SHARED
            Mutexes created  with  this  attributes  object  can  be  shared
            between  any  threads  that have access to the memory containing
            the object, including threads in different processes.

     pthread_mutexattr_getpshared() places the value of  the  process-shared
     attribute  of  the  mutex  attributes object referred to by attr in the
     location pointed to by pshared.

     pthread_mutexattr_setpshared() sets the  value  of  the  process-shared
     attribute  of  the  mutex  attributes object referred to by attr to the
     value specified in pshared.

     If attr does not refer to an initialized mutex attributes  object,  the
     behavior is undefined.

RETURN VALUE

     On success, these functions return 0.  On error, they return a positive
     error number.

ERRORS

     pthread_mutexattr_setpshared() can fail with the following errors:

     EINVAL The value specified in pshared is invalid.

     ENOTSUP
            pshared is PTHREAD_PROCESS_SHARED but  the  implementation  does
            not support process-shared mutexes.

CONFORMING TO

     POSIX.1-2001, POSIX.1-2008.

SEE ALSO

     pthread_mutexattr_init(3), pthreads(7)

COLOPHON

     This page is part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs, and the
     latest version of this page, can be found at
     https://www.kernel.org/doc/man-pages/.

Linux 2017-09-13 PTHREAD_MUTEXATTR_GETPSHARED(3)