VMS Help CC, Language topics, Builtin Functions, Locate Character  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The _LOCC function locates the first character in a string matching
  the target character.

  Syntax:

       unsigned short _LOCC(char __target, unsigned short __length,
                            const char *__string, ...);

  where the optional argument (...) is char **position.