pthread_mutexattr_getpshared(3) Linux Man Page

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 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.

Standards

POSIX.1-2008.

History

POSIX.1-2001.

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