pthread_mutexattr_getpshared()

Get the process-shared attribute from a mutex attribute object

Synopsis:

#include <pthread.h>

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

Arguments:

attr: A pointer to the pthread_mutexattr_t object that you want to get the attribute from.
pshared: A pointer to a location where the function can store the process-shared attribute.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The pthread_mutexattr_getpshared() function gets the process-shared attribute from the mutex attribute object attr and stores it in the memory pointed to by pshared. The possible values are:

PTHREAD_PROCESS_SHARED — any thread that has access to the memory where the mutex is allocated can operate on it, even if the mutex is allocated in memory that's shared by multiple processes.
PTHREAD_PROCESS_PRIVATE — the mutex can be accessed only by threads created within the same process as the thread that initialized the mutex; if threads from other processes try to access the PTHREAD_PROCESS_PRIVATE mutex, the behavior is undefined.

Note: (QNX Neutrino 7.0.1 or later) If you started procnto with the -s option, set the process-shared attribute to PTHREAD_PROCESS_SHARED for any mutexes that are shared between processes. For more information, see “Safely sharing mutexes, barriers, and reader/writer locks between processes” in the “QNX Neutrino Microkernel” chapter of the System Architecture guide.

Returns:

EOK: Success.
EINVAL: The mutex attribute object specified by attr is invalid.

Classification:

POSIX 1003.1 TSH

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes