pthread_rwlockattr_getpshared() — Get the processed-shared read or write lock attribute

#define _OPEN_THREADS
#include <pthread.h>

int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *attr, int *pshared);

SUSV3:

#define _UNIX03_THREADS 
#include <pthread.h>
int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *
                                   __restrict__attr, 
                                  int * __restrict__pshared);

The valid values for the attribute pshared are:

PTHREAD_PROCESS_SHARED

Permits a read or write lock to be operated upon by any thread that has access to the memory where the read or write lock is allocated, even if the read or write lock is allocated in memory that is shared by multiple processes.

PTHREAD_PROCESS_PRIVATE

A read or write lock can only be operated upon by threads created within the same process as the thread that initialized the read or write lock. When a new process is created by the parent process it will receive a different copy of the private read or write lock and this new read or write lock can only be used to serialize between threads in the child process. The default value of the attributed is PTHREAD_PROCESS_PRIVATE.

If unsuccessful, pthread_rwlockattr_getpshared() returns -1 and sets errno to one of the following values:

Error Code

Description

EINVAL

The value specified for attr is not valid.