1 /* $NetBSD: fwrite.c,v 1.18 2018/02/04 01:13:45 mrg Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)fwrite.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: fwrite.c,v 1.18 2018/02/04 01:13:45 mrg Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include "reentrant.h" 48 #include "local.h" 49 #include "fvwrite.h" 50 51 /* 52 * Write `count' objects (each size `size') from memory to the given file. 53 * Return the number of whole objects written. 54 */ 55 size_t 56 fwrite(const void *buf, size_t size, size_t count, FILE *fp) 57 { 58 size_t n; 59 struct __suio uio; 60 struct __siov iov; 61 62 /* 63 * SUSv2 requires a return value of 0 for a count or a size of 0. 64 */ 65 if ((n = count * size) == 0) 66 return 0; 67 68 iov.iov_base = __UNCONST(buf); 69 uio.uio_resid = iov.iov_len = n; 70 uio.uio_iov = &iov; 71 uio.uio_iovcnt = 1; 72 73 /* 74 * The usual case is success (__sfvwrite returns 0); 75 * skip the divide if this happens, since divides are 76 * generally slow and since this occurs whenever size==0. 77 */ 78 FLOCKFILE(fp); 79 if (__sfvwrite(fp, &uio) != 0) 80 count = ((n - uio.uio_resid) / size); 81 FUNLOCKFILE(fp); 82 return count; 83 } 84