VMS Help DCE_THREADS, Application Routines, sigwait  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  NAME

      sigwait - Causes a thread to wait for an asynchronous signal

  SYNOPSIS

      #include <pthread.h>

      int sigwait( sigset_t *set );

  PARAMETERS

      set                Set of asynchronous pending signals from which
                         this routine chooses one signal on which the
                         calling thread will wait.

  DESCRIPTION

  This routine causes a thread to wait for an asynchronous signal by
  choosing a pending signal from set, atomically clearing it from the
  system's set of pending signals and returning that signal number.  If no
  signal in set is pending at the time of the call, the thread is blocked
  until one or more signals becomes pending.  The signals defined by set
  may be unblocked during the call to this routine and will be blocked
  when the thread returns from the call unless some other thread is
  currently waiting for one of those signals.

  If more than one thread is using this routine to wait for the same
  signal, only one of these threads will return from this routine with the
  signal number.

  RETURN VALUES

  Possible return values are as follows:

    Return          Error      Description
    __________________________________________________
    Signal number              Successful completion.

    -1             [EINVAL]    The value specified by set is
                               invalid.

  RELATED INFORMATION

      FUNCTIONS: pthread_cancel
                 pthread_setasynccancel