UNGETC(3S) (C Programming Language Utilities) UNGETC(3S)
NAME
ungetc - push character back into input stream
SYNOPSIS
#include <stdio.h>
int ungetc (c, stream)
int c;
FILE *stream;
DESCRIPTION
ungetc inserts the character c into the buffer associated
with an input stream. That character, c, will be returned
by the next getc(3S) call on that stream. ungetc returns c,
and leaves the file stream unchanged.
One character of pushback is guaranteed, provided something
has already been read from the stream and the stream is
actually buffered.
If c equals EOF, ungetc does nothing to the buffer and
returns EOF.
fseek(3S) erases all memory of inserted characters.
SEE ALSO
fseek(3S), getc(3S), setbuf(3S), stdio(3S).
DIAGNOSTICS
ungetc returns EOF if it cannot insert the character.
BUGS
When stream is stdin, one character may be pushed back onto
the buffer without a previous read statement.
Page 1 May 1989