ungetc.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1988 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI" /* from S5R2 2.1 */
/*LINTLIBRARY*/
#include <stdio.h>
int
ungetc(c, iop)
int c;
register FILE *iop;
{
if(c == EOF)
return(EOF);
if((iop->_flag & (_IOREAD|_IORW)) == 0)
return(EOF);
if (iop->_base == NULL) /* get buffer if we don't have one */
_findbuf(iop);
if((iop->_flag & _IOREAD) == 0 || iop->_ptr <= iop->_base)
if(iop->_ptr == iop->_base && iop->_cnt == 0)
++iop->_ptr;
else
return(EOF);
if (*--iop->_ptr != c) *iop->_ptr = c; /* was *--iop->_ptr = c; */
++iop->_cnt;
return(c);
}