src/system/libroot/posix/stdio/fflush.c

   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. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char rcsid[] = "$OpenBSD: fflush.c,v 1.2 1996/08/19 08:32:26 tholo Exp $";
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include <errno.h>
  42 #include <stdio.h>
  43
  44 #include <errno_private.h>
  45
  46 #include "local.h"
  47
  48 /* Flush a single file, or (if fp is NULL) all files.  */
  49 int
  50 fflush(fp)
  51         register FILE *fp;
  52 {
  53         if (fp == NULL)
  54                 return (_fwalk(__sflush));
  55         if ((fp->_flags & (__SWR | __SRW)) == 0) {
  56                 __set_errno(EBADF);
  57                 return (EOF);
  58         }
  59         return (__sflush(fp));
  60 }
  61
  62 int
  63 __sflush(fp)
  64         register FILE *fp;
  65 {
  66         register unsigned char *p;
  67         register int n, t;
  68
  69         t = fp->_flags;
  70         if ((t & __SWR) == 0)
  71                 return (0);
  72
  73         if ((p = fp->_bf._base) == NULL)
  74                 return (0);
  75
  76         n = fp->_p - p;         /* write this much */
  77
  78         /*
  79          * Set these immediately to avoid problems with longjmp and to allow
  80          * exchange buffering (via setvbuf) in user write function.
  81          */
  82         fp->_p = p;
  83         fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
  84
  85         for (; n > 0; n -= t, p += t) {
  86                 t = (*fp->_write)(fp->_cookie, (char *)p, n);
  87                 if (t <= 0) {
  88                         fp->_flags |= __SERR;
  89                         return (EOF);
  90                 }
  91         }
  92         return (0);
  93 }