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

  Compares not more than maxchar characters of two ASCII character
  strings and returns a negative, 0, or positive integer, indicating
  that the ASCII values of the individual characters in the first
  string are less than, equal to, or greater than the values in the
  second string.

  Syntax:

       #include <string.h>

       int strncmp(const char *str_1, const char *str_2,
                   size_t maxchar);