binary_search
front = binary_search(string, front, back);
char *binary_search(char *, char *, char *);
u_char *binary_search(u_char *, u_char *, u_char *);
front = binary_search(string, front, back);
front = binary_search(tname, front, back);
static char *binary_search(char *, char *, char *);