pthread_mu...getpshared(3)  Library Functions Manual  pthread_mu...getpshared(3)

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

LIBRARY
     POSIX threads library (libpthread, -lpthread)

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
     These functions get and set the process-shared attribute in a mutex attrib-
     utes 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 at-
     tribute 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 at-
     tribute 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 be-
     havior is undefined.

RETURN VALUE
     On success, these functions return 0.  On error, they return a positive er-
     ror 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.

STANDARDS
     POSIX.1-2008.

HISTORY
     POSIX.1-2001.

SEE ALSO
     pthread_mutexattr_init(3), pthreads(7)

Linux man-pages 6.18		   2026-02-08	      pthread_mu...getpshared(3)