The function shall apply a read lock to the read-write lock referenced by rwlock as in the pthread_rwlock_rdlock(). However, if the lock cannot be acquired wither out waiting for other threads to unlock the lock, this wait shall be terminated when the specified timeout expires. The timeout shall expire when the absolute time specified by abs_timeout passes, as measured by the clock on which timeouts are based (that is, when the value of that clock equals or exceeds abs_timeout), or if the absolute time specified by abs_timeout has already been passed at the time of the call. If the Timers option is supported, the timeout shall be based on the CLOCK_REALTIME clock. If the Timers option is not supported, the timeout shall be based on the system clock as returned by the time( ) function. The resolution of the timeout shall be the resolution of the clock on which it is based. The timespec data type is defined in the 'time.h' header. Under no circumstances shall the function fail with a timeout if the lock can be acquired immediately. The abs_timeout parameter need not be checked if the lock can be immediately acquired. If a signal that causes a signal handler to be executed is delivered to a thread blocked on a read-write lock via a call to pthread_rwlock_timedwrlock( ), upon return from the signal handler the thread shall resume waiting for the lock as if it was not interrupted. Shall return zero if the lock for writing on the read-write lock object referenced by rwlock is acquired. Otherwise, an error number shall be returned to indicate the error pthread_rwlock_timedwrlock( ) function shall fail if: [ETIMEDOUT] The lock could not be acquired before the specified timeout expired. The function shall not return an error code of [EINTR].