NAME

ungetc − push character back into input stream

SYNOPSIS

#include <stdio.h>

int ungetc (c, stream)
int c;
FILE ∗stream;

HP-UX COMPATIBILITY

Level: HP-UX/RUN ONLY

Origin: System V

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.  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, 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). 

DIAGNOSTICS

Ungetc returns EOF if it cannot insert the character. 

Hewlett-Packard  —  last mod. May 11, 2021