fflush.c revision 131592
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software contributed to Berkeley by 61573Srgrimes * Chris Torek. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 161573Srgrimes * 3. All advertising materials mentioning features or use of this software 171573Srgrimes * must display the following acknowledgement: 181573Srgrimes * This product includes software developed by the University of 191573Srgrimes * California, Berkeley and its contributors. 201573Srgrimes * 4. Neither the name of the University nor the names of its contributors 211573Srgrimes * may be used to endorse or promote products derived from this software 221573Srgrimes * without specific prior written permission. 231573Srgrimes * 241573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 251573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 261573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 271573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 281573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 291573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 301573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 311573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 321573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 331573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 341573Srgrimes * SUCH DAMAGE. 351573Srgrimes */ 361573Srgrimes 371573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 381573Srgrimesstatic char sccsid[] = "@(#)fflush.c 8.1 (Berkeley) 6/4/93"; 391573Srgrimes#endif /* LIBC_SCCS and not lint */ 4092986Sobrien#include <sys/cdefs.h> 4192986Sobrien__FBSDID("$FreeBSD: head/lib/libc/stdio/fflush.c 131592 2004-07-04 20:17:00Z cperciva $"); 421573Srgrimes 4371579Sdeischen#include "namespace.h" 441573Srgrimes#include <errno.h> 451573Srgrimes#include <stdio.h> 4671579Sdeischen#include "un-namespace.h" 4771579Sdeischen#include "libc_private.h" 481573Srgrimes#include "local.h" 491573Srgrimes 5072373Sdeischenstatic int sflush_locked(FILE *); 5172373Sdeischen 5271579Sdeischen/* 5371579Sdeischen * Flush a single file, or (if fp is NULL) all files. 5471579Sdeischen * MT-safe version 5571579Sdeischen */ 5613545Sjulianint 5771579Sdeischenfflush(FILE *fp) 581573Srgrimes{ 5913545Sjulian int retval; 601573Srgrimes 611573Srgrimes if (fp == NULL) 6272373Sdeischen return (_fwalk(sflush_locked)); 6335129Sjb FLOCKFILE(fp); 64131592Scperciva 65131592Scperciva /* 66131592Scperciva * There is disagreement about the correct behaviour of fflush() 67131592Scperciva * when passed a file which is not open for reading. According to 68131592Scperciva * the ISO C standard, the behaviour is undefined. 69131592Scperciva * Under linux, such an fflush returns success and has no effect; 70131592Scperciva * under Windows, such an fflush is documented as behaving instead 71131592Scperciva * as fpurge(). 72131592Scperciva * Given that applications may be written with the expectation of 73131592Scperciva * either of these two behaviours, the only safe (non-astonishing) 74131592Scperciva * option is to return EBADF and ask that applications be fixed. 75131592Scperciva */ 761573Srgrimes if ((fp->_flags & (__SWR | __SRW)) == 0) { 771573Srgrimes errno = EBADF; 7813545Sjulian retval = EOF; 7971579Sdeischen } else 8013545Sjulian retval = __sflush(fp); 8135129Sjb FUNLOCKFILE(fp); 8213545Sjulian return (retval); 831573Srgrimes} 841573Srgrimes 8571579Sdeischen/* 8671579Sdeischen * Flush a single file, or (if fp is NULL) all files. 8771579Sdeischen * Non-MT-safe version 8871579Sdeischen */ 8913545Sjulianint 9071579Sdeischen__fflush(FILE *fp) 911573Srgrimes{ 9271579Sdeischen int retval; 931573Srgrimes 9471579Sdeischen if (fp == NULL) 9572373Sdeischen return (_fwalk(sflush_locked)); 9671579Sdeischen if ((fp->_flags & (__SWR | __SRW)) == 0) { 9771579Sdeischen errno = EBADF; 9871579Sdeischen retval = EOF; 9971579Sdeischen } else 10071579Sdeischen retval = __sflush(fp); 10171579Sdeischen return (retval); 10271579Sdeischen} 10371579Sdeischen 10471579Sdeischenint 10571579Sdeischen__sflush(FILE *fp) 10671579Sdeischen{ 10771579Sdeischen unsigned char *p; 10871579Sdeischen int n, t; 10971579Sdeischen 1101573Srgrimes t = fp->_flags; 1111573Srgrimes if ((t & __SWR) == 0) 1121573Srgrimes return (0); 1131573Srgrimes 1141573Srgrimes if ((p = fp->_bf._base) == NULL) 1151573Srgrimes return (0); 1161573Srgrimes 1171573Srgrimes n = fp->_p - p; /* write this much */ 1181573Srgrimes 1191573Srgrimes /* 1201573Srgrimes * Set these immediately to avoid problems with longjmp and to allow 1211573Srgrimes * exchange buffering (via setvbuf) in user write function. 1221573Srgrimes */ 1231573Srgrimes fp->_p = p; 1241573Srgrimes fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size; 1251573Srgrimes 1261573Srgrimes for (; n > 0; n -= t, p += t) { 12782838Sache t = _swrite(fp, (char *)p, n); 1281573Srgrimes if (t <= 0) { 1291573Srgrimes fp->_flags |= __SERR; 1301573Srgrimes return (EOF); 1311573Srgrimes } 1321573Srgrimes } 1331573Srgrimes return (0); 1341573Srgrimes} 13572373Sdeischen 13672373Sdeischenstatic int 13772373Sdeischensflush_locked(FILE *fp) 13872373Sdeischen{ 13972373Sdeischen int ret; 14072373Sdeischen 14172373Sdeischen FLOCKFILE(fp); 14272373Sdeischen ret = __sflush(fp); 14372373Sdeischen FUNLOCKFILE(fp); 14472373Sdeischen return (ret); 14572373Sdeischen} 146