ungetc(3) BSD Library Functions Manual ungetc(3)
NAME
ungetc -- un-get character from input stream
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdio.h>
int
ungetc(int c, FILE *stream);
DESCRIPTION
The ungetc() function pushes the character c (converted to an unsigned
char) back onto the input stream pointed to by stream. The pushed-back
characters will be returned (in reverse order) by subsequent reads on the
stream. A successful intervening call to one of the file positioning
functions (fseek(3), fsetpos(3), or rewind(3)), using the same stream,
will discard the pushed-back characters.
Only one character of push-back is guaranteed, but as long as there is
sufficient memory, an effectively infinite amount of push-back is
allowed.
If a character is successfully pushed-back, the end-of-file indicator for
the stream is cleared. The file-position indicator is decremented by
each successful call to ungetc(); if its value was 0 before a call, its
value is unspecified after the call.
RETURN VALUES
The ungetc() function returns the character pushed-back after the conver-
sion, or EOF if the operation fails. If the value of the argument c
character equals EOF, the operation will fail and the stream will remain
unchanged.
SEE ALSO
fseek(3), getc(3), setvbuf(3), ungetwc(3)
STANDARDS
The ungetc() function conforms to ISO/IEC 9899:1990 (``ISO C90'').
BSD June 4, 1993 BSD
Mac OS X 10.8 - Generated Fri Aug 31 16:53:58 CDT 2012