unvis
int unvis(char *, int, int *, int);
switch (unvis(&t, c, &state, flag)) {
if (unvis(&t, c, &state, UNVIS_END) == UNVIS_VALID) {
switch(ret = unvis(&outc, (char)c, &state, eflags)) {
if (unvis(&outc, (char)0, &state, eflags | UNVIS_END) == UNVIS_VALID)