PTHREAD_MUTEXATTR_GETPSHARED(3)                                         Linux Programmer's Manual                                        PTHREAD_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 *restrict attr,
                             int *restrict 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 op‐
       eration 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)

Linux                                                                          2021-03-22                                                PTHREAD_MUTEXATTR_GETPSHARED(3)