1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)fpurge.c 8.1 (Berkeley) 6/4/93 33 * $FreeBSD: src/lib/libc/stdio/fpurge.c,v 1.11 2007/01/09 00:28:06 imp Exp $ 34 */ 35 36 #include "namespace.h" 37 #include <errno.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include "un-namespace.h" 41 #include "local.h" 42 #include "libc_private.h" 43 44 /* 45 * fpurge: like fflush, but without writing anything: leave the 46 * given FILE's buffer empty. 47 */ 48 int 49 fpurge(FILE *fp) 50 { 51 int retval; 52 FLOCKFILE(fp); 53 if (!fp->pub._flags) { 54 errno = EBADF; 55 retval = EOF; 56 } else { 57 if (HASUB(fp)) 58 FREEUB(fp); 59 fp->pub._p = fp->_bf._base; 60 fp->pub._r = 0; 61 fp->pub._w = fp->pub._flags & (__SLBF|__SNBF) ? 0 : fp->_bf._size; 62 retval = 0; 63 } 64 FUNLOCKFILE(fp); 65 return (retval); 66 } 67