#include <pthread.h> int pthread_rwlock_tryrdlock(pthread_rwlock_t *rwlock);
pthread_rwlock_tryrdlock(3THR) applies a read lock as in pthread_rwlock_rdlock() with the exception that the function fails if any thread holds a write lock on rwlock or there are writers blocked on rwlock. (For Solaris threads, see rw_tryrdlock(3THR).)
pthread_rwlock_tryrdlock() returns zero if the lock for reading on the read-write lock object referenced by rwlock is acquired. Otherwise an error number is returned to indicate the error.