Locks the specified reader-writer lock for writing, it it is available.
#include <pthread.h>
int pthread_rwlock_trywrlock (
pthread_rwlock_t *rwlp);
(IN) Points to the reader lock.
If successful, returns zero; otherwise, returns a nonzero error code:
If the lock is immediately available, pthread_rwlock_trywrlock function acquires the writing lock. If the lock is not available, the function returns immediately with an EBUSY error. It does not block.