The function int pthread_cond_destroy(pthread_cond_t *cond); shall destroy the given condition variable specified by cond; the object becomes, in effect, uninitialized. An implementation may cause pthread_cond_destroy() to set the object referenced by cond to an invalid value. A destroyed condition variable object can be reinitialized using pthread_cond_init(); the results of otherwise referencing the object after it has been destroyed are undefined. It shall be safe to destroy an initialized condition variable upon which no threads are currently blocked. Attempting to destroy a condition variable upon which other threads are currently blocked results in undefined behavior. If successful, the pthread_cond_destroy() function shall return zero; The pthread_cond_destroy() function may fail if: [EBUSY] The implementation has detected an attempt to destroy the object referenced by cond while it is referenced (for example, while being used in a pthread_cond_wait() or pthread_cond_timedwait( )) by another thread. [EINVAL] The value specified by cond is invalid. The function shall not return an error code of [EINTR].