/*-

 * Copyright (c) 1990, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Chris Torek.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 * © Portions copyright (c) 2005-2006  Nokia Corporation.  All rights reserved.

 */

#if defined(LIBC_SCCS) && !defined(lint)

static char sccsid[] = "@(#)fflush.c	8.1 (Berkeley) 6/4/93";

#endif /* LIBC_SCCS and not lint */

#include <sys/cdefs.h>

#ifndef __SYMBIAN32__

__FBSDID("$FreeBSD: src/lib/libc/stdio/fflush.c,v 1.13 2004/07/04 20:17:00 cperciva Exp $");

#endif

#include "namespace.h"

#include <errno.h>

#include <stdio.h>

#include "un-namespace.h"

#include "libc_private.h"

#include "local.h"

static int	sflush_locked(FILE *);

/*

 * Flush a single file, or (if fp is NULL) all files.

 * MT-safe version

 */

EXPORT_C int

fflush(FILE *fp)

{

	int retval;

	if (fp == NULL)

		return (_fwalk(sflush_locked));

	FLOCKFILE(fp);

	/*

	 * There is disagreement about the correct behaviour of fflush()

	 * when passed a file which is not open for reading.  According to

	 * the ISO C standard, the behaviour is undefined.

	 * Under linux, such an fflush returns success and has no effect;

	 * under Windows, such an fflush is documented as behaving instead

	 * as fpurge().

	 * Given that applications may be written with the expectation of

	 * either of these two behaviours, the only safe (non-astonishing)

	 * option is to return EBADF and ask that applications be fixed.

	 */

	if ((fp->_flags & (__SWR | __SRW)) == 0) {

		errno = EBADF;

		retval = EOF;

	} else

		retval = __sflush(fp);

	FUNLOCKFILE(fp);

	return (retval);

}

/*

 * Flush a single file, or (if fp is NULL) all files.

 * Non-MT-safe version

 */

int

__fflush(FILE *fp)

{

	int retval;

	if (fp == NULL)

		return (_fwalk(sflush_locked));

	if ((fp->_flags & (__SWR | __SRW)) == 0) {

		errno = EBADF;

		retval = EOF;

	} else

		retval = __sflush(fp);

	return (retval);

}

int

__sflush(FILE *fp)

{

	unsigned char *p;

	int n, t;

	t = fp->_flags;

	if ((t & __SWR) == 0)

		return (0);

	if ((p = fp->_bf._base) == NULL)

		return (0);

	n = fp->_p - p;		/* write this much */

	/*

	 * Set these immediately to avoid problems with longjmp and to allow

	 * exchange buffering (via setvbuf) in user write function.

	 */

	fp->_p = p;

	fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;

	for (; n > 0; n -= t, p += t) {

		t = _swrite(fp, (char *)p, n);

		if (t <= 0) {

			fp->_flags |= __SERR;

			return (EOF);

		}

	}

	return (0);

}

static int

sflush_locked(FILE *fp)

{

	int	ret;

	FLOCKFILE(fp);

	ret = __sflush(fp);

	FUNLOCKFILE(fp);

	return (ret);

}