_next_char
(void) _next_char(f);
_data_navigation, _next_char, /* REQ_NEXT_CHAR */
extern int _next_char(FORM *); /* REQ_NEXT_CHAR */
if (':' == _next_char(pOptString)) { /* is the next letter a colon? */
if ('\0' != _next_char(pArgString)) { /* argument in this argv? */