cc [ flag ... ] file ... -lw [ library ... ]
#include <stdio.h> #include <widec.h>
int ungetwc(int c, FILE *stream);
MT-Safe
One character of pushback is guaranteed provided something has been read from the stream and the stream is actually buffered. In the case that stream is stdin, one character may be pushed back onto the buffer without a previous read statement.
If c equals EOF , ungetwc() does nothing to the buffer and returns EOF .
An fseek(3S) erases all memory of pushed back characters.