1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1988 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984 AT&T */ 28 /* All Rights Reserved */ 29 30 #pragma ident "%Z%%M% %I% %E% SMI" /* from S5R2 2.1 */ 31 32 /*LINTLIBRARY*/ 33 #include <stdio.h> 34 35 int 36 ungetc(c, iop) 37 int c; 38 register FILE *iop; 39 { 40 if(c == EOF) 41 return(EOF); 42 if((iop->_flag & (_IOREAD|_IORW)) == 0) 43 return(EOF); 44 45 if (iop->_base == NULL) /* get buffer if we don't have one */ 46 _findbuf(iop); 47 48 if((iop->_flag & _IOREAD) == 0 || iop->_ptr <= iop->_base) 49 if(iop->_ptr == iop->_base && iop->_cnt == 0) 50 ++iop->_ptr; 51 else 52 return(EOF); 53 if (*--iop->_ptr != c) *iop->_ptr = c; /* was *--iop->_ptr = c; */ 54 ++iop->_cnt; 55 return(c); 56 } 57