/sys$common/syshlp/helplib.hlb CC, Run-time functions, ualarm  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Sets or changes the timeout of interval timers.

  Syntax:

        #include <unistd.h>

        useconds_t ualarm (useconds_t mseconds,
                             useconds_t interval);