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 processesin the
QNX Neutrino Microkernelchapter of the System Architecture guide.
Returns:
- EOK
- Success.
- EINVAL
- The mutex attribute object specified by attr is invalid.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Interrupt handler | No |
| Signal handler | Yes |
| Thread | Yes |
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