1/* $NetBSD: fpurge.c,v 1.12 2003/01/18 11:29:52 thorpej Exp $ */ 2 3/*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35#include <sys/cdefs.h> 36#if defined(LIBC_SCCS) && !defined(lint) 37#if 0 38static char sccsid[] = "@(#)fpurge.c 8.1 (Berkeley) 6/4/93"; 39#else 40__RCSID("$NetBSD: fpurge.c,v 1.12 2003/01/18 11:29:52 thorpej Exp $"); 41#endif 42#endif /* LIBC_SCCS and not lint */ 43 44#include <assert.h> 45#include <errno.h> 46#include <stdio.h> 47#include <stdlib.h> 48#include <wchar.h> 49#include "reentrant.h" 50#include "local.h" 51 52/* 53 * fpurge: like fflush, but without writing anything: leave the 54 * given FILE's buffer empty. 55 */ 56int 57fpurge(fp) 58 FILE *fp; 59{ 60 61 _DIAGASSERT(fp != NULL); 62 63 if (fp->_flags == 0) { 64 errno = EBADF; 65 return (EOF); 66 } 67 FLOCKFILE(fp); 68 if (HASUB(fp)) 69 FREEUB(fp); 70 WCIO_FREE(fp); 71 fp->_p = fp->_bf._base; 72 fp->_r = 0; 73 fp->_w = fp->_flags & (__SLBF|__SNBF) ? 0 : fp->_bf._size; 74 FUNLOCKFILE(fp); 75 return (0); 76} 77