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

  Allows you to specify the way in which the signal sig is to be
  handled:  use the default handling for the signal, ignore the
  signal, or call the signal handler at the address specified.

  Syntax:

       #include <signal.h>

       void (*signal(int sig, void (*func) (int))) (int);