Description

   When threads are present, this routine causes a thread to wait
   for the specified condition variable cond to be signaled or
   broadcast.

   Calling this routine in a single-threaded environment is a coding
   error. Because no other thread exists to issue a call to tis_
   cond_signal() or tis_cond_broadcast(),  using this routine in a
   single-threaded environment forces the program to exit.

   For further information about actions taken when threads are
   present, refer to the pthread_cond_wait() description.