__ungetc
if (__ungetc((*linep)[--linelen],
extern int __ungetc(int, FILE *);
ret = __ungetc(c, fp);
if (__ungetc((unsigned char)buf[len], fp) == EOF)
__ungetc(*(u_char *)p, fp);
(void) __ungetc(*(u_char *)p, fp);
(void) __ungetc(c, fp);
(void) __ungetc(c, fp);