cc [options] -Kthread file
int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr, int pshared); int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *attr, int *pshared);
pthread_rwlockattr_getpshared obtains the value of the process-shared attribute from the initialized attributes object pointed to by attr.
The process-shared attribute is set to PTHREAD_PROCESS_SHARED to permit a read-write lock to be operated upon by any thread that has access to the memory where the read-write lock is allocated, even if the read-write lock is allocated in memory that is shared by multiple processes. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE, the read-write lock will only be operated upon by threads created within the same process as the thread that initialized the read-write lock; if threads of differing processes attempt to operate on such a read-write lock, the behavior is undefined. The default value of the process-shared attribute is PTHREAD_PROCESS_PRIVATE.
pthread_rwlockattr_setpshared function returns zero on success. Otherwise, an error number is returned.
pthread_rwlockattr_setpshared returns the following value if the corresponding condition is detected: