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

  Concatenates str_2, including the terminating null character, to
  the end of str_1.

  Syntax:

       #include <string.h>

       char *strcat(char *str_1, const char *str_2);