1 /* $OpenBSD: fwrite.c,v 1.10 2009/11/21 09:53:44 guenther Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <stdio.h> 35 #include "local.h" 36 #include "fvwrite.h" 37 38 /* 39 * Write `count' objects (each size `size') from memory to the given file. 40 * Return the number of whole objects written. 41 */ 42 size_t 43 fwrite(const void *buf, size_t size, size_t count, FILE *fp) 44 { 45 size_t n; 46 struct __suio uio; 47 struct __siov iov; 48 int ret; 49 50 /* 51 * ANSI and SUSv2 require a return value of 0 if size or count are 0. 52 */ 53 if ((n = count * size) == 0) 54 return (0); 55 56 iov.iov_base = (void *)buf; 57 uio.uio_resid = iov.iov_len = n; 58 uio.uio_iov = &iov; 59 uio.uio_iovcnt = 1; 60 61 /* 62 * The usual case is success (__sfvwrite returns 0); 63 * skip the divide if this happens, since divides are 64 * generally slow and since this occurs whenever size==0. 65 */ 66 FLOCKFILE(fp); 67 _SET_ORIENTATION(fp, -1); 68 ret = __sfvwrite(fp, &uio); 69 FUNLOCKFILE(fp); 70 if (ret == 0) 71 return (count); 72 return ((n - uio.uio_resid) / size); 73 } 74