lib/libc/stdio/fwrite.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  * @(#)fwrite.c 8.1 (Berkeley) 6/4/93
  37  * $FreeBSD: src/lib/libc/stdio/fwrite.c,v 1.7 1999/08/28 00:01:07 peter Exp $
  38  * $DragonFly: src/lib/libc/stdio/fwrite.c,v 1.5 2005/07/23 20:23:06 joerg Exp $
  39  */
  40
  41 #include "namespace.h"
  42 #include <sys/types.h>
  43 #include <stdio.h>
  44 #include "un-namespace.h"
  45 #include "local.h"
  46 #include "priv_stdio.h"
  47 #include "libc_private.h"
  48
  49 /*
  50  * Write `count' objects (each size `size') from memory to the given file.
  51  * Return the number of whole objects written.
  52  */
  53 size_t
  54 fwrite(const void *buf, size_t size, size_t count, FILE *fp)
  55 {
  56         size_t n;
  57         struct __suio uio;
  58         struct __siov iov;
  59
  60         iov.iov_base = __DECONST(void *, buf);
  61         uio.uio_resid = iov.iov_len = n = count * size;
  62         uio.uio_iov = &iov;
  63         uio.uio_iovcnt = 1;
  64
  65         FLOCKFILE(fp);
  66         /*
  67          * The usual case is success (__sfvwrite returns 0);
  68          * skip the divide if this happens, since divides are
  69          * generally slow and since this occurs whenever size==0.
  70          */
  71         if (__sfvwrite(fp, &uio) != 0)
  72             count = (n - uio.uio_resid) / size;
  73         FUNLOCKFILE(fp);
  74         return (count);
  75 }