1 /* FWRITE.C

     2  * 

     3  * Portions Copyright (c) 1990-2005 Nokia Corporation and/or its subsidiary(-ies).

     4  * All rights reserved.

     5  */

     6 

     7 /*

     8  * Copyright (c) 1990 The Regents of the University of California.

     9  * All rights reserved.

    10  *

    11  * Redistribution and use in source and binary forms are permitted

    12  * provided that the above copyright notice and this paragraph are

    13  * duplicated in all such forms and that any documentation,

    14  * advertising materials, and other materials related to such

    15  * distribution and use acknowledge that the software was developed

    16  * by the University of California, Berkeley.  The name of the

    17  * University may not be used to endorse or promote products derived

    18  * from this software without specific prior written permission.

    19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

    20  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

    21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

    22  */

    23 

    24 /*

    25 FUNCTION

    26 <<fwrite>>---write array elements

    27 

    28 INDEX

    29 	fwrite

    30 

    31 ANSI_SYNOPSIS

    32 	#include <stdio.h>

    33 	size_t fwrite(const void *<[buf]>, size_t <[size]>,

    34 		      size_t <[count]>, FILE *<[fp]>);

    35 

    36 TRAD_SYNOPSIS

    37 	#include <stdio.h>

    38 	size_t fwrite(<[buf]>, <[size]>, <[count]>, <[fp]>)

    39 	char *<[buf]>;

    40 	size_t <[size]>;

    41 	size_t <[count]>;

    42 	FILE *<[fp]>;

    43 

    44 DESCRIPTION

    45 <<fwrite>> attempts to copy, starting from the memory location

    46 <[buf]>, <[count]> elements (each of size <[size]>) into the file or

    47 stream identified by <[fp]>.  <<fwrite>> may copy fewer elements than

    48 <[count]> if an error intervenes.

    49 

    50 <<fwrite>> also advances the file position indicator (if any) for

    51 <[fp]> by the number of @emph{characters} actually written.

    52 

    53 RETURNS

    54 If <<fwrite>> succeeds in writing all the elements you specify, the

    55 result is the same as the argument <[count]>.  In any event, the

    56 result is the number of complete elements that <<fwrite>> copied to

    57 the file.

    58 

    59 PORTABILITY

    60 ANSI C requires <<fwrite>>.

    61 

    62 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,

    63 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.

    64 */

    65 

    66 #include <stdio.h>

    67 #include <string.h>

    68 #include "LOCAL.H"

    69 #include "FVWRITE.H"

    70 

    71 /*

    72  * Write `count' objects (each size `size') from memory to the given file.

    73  * Return the number of whole objects written.

    74  */

    75 

    76 EXPORT_C size_t

    77 fwrite (const void *buf, size_t size, size_t count, FILE * fp)

    78 {

    79   size_t n;

    80   struct __suio uio;

    81   struct __siov iov;

    82 

    83   iov.iov_base = buf;

    84   uio.uio_resid = iov.iov_len = n = count * size;

    85   uio.uio_iov = &iov;

    86   uio.uio_iovcnt = 1;

    87 

    88   /*

    89    * The usual case is success (__sfvwrite returns 0);

    90    * skip the divide if this happens, since divides are

    91    * generally slow and since this occurs whenever size==0.

    92    */

    93 

    94   if (__sfvwrite (fp, &uio) == 0)

    95     return count;

    96   return (n - uio.uio_resid) / size;

    97 }