UNGETC(3) | Library Functions Manual | UNGETC(3) |
ungetc
—
#include <stdio.h>
int
ungetc
(int
c, FILE
*stream);
ungetc
() function pushes the character
c (converted to an unsigned char) back onto the input
stream pointed to by stream. The pushed-backed
characters will be returned by subsequent reads on the stream (in reverse
order). A successful intervening call, using the same stream, to one of the
file positioning functions
(fseek(3),
fsetpos(3), or
rewind(3)) will discard the
pushed back characters.
One character of push-back is guaranteed, but as long as there is sufficient memory, an effectively infinite amount of pushback is allowed.
If a character is successfully pushed-back, the end-of-file indicator for the stream is cleared.
ungetc
() function returns the character pushed-back
after the conversion, 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.
ungetc
() function conforms to ANSI
X3.159-1989 (“ANSI C89”) and IEEE
Std 1003.1-2001 (“POSIX.1”).
ungetc
() function appeared in
Version 7 AT&T UNIX.
April 30, 2010 | NetBSD 9.0 |