VMS Help CC, Run-time functions, bsearch  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Performs a binary search.  It searches an array of sorted objects
  for a specified object.

  Syntax:

        #include <stdlib.h>

        void *bsearch (const void *key,
                       const void *base,
                       size_t nmemb,
                       size_t size,
                       int (*compar) (const void *, const void *));