1<html lang="en"> 2<head> 3<title>fwrite - Untitled</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Untitled"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="start" href="index.html#Top"> 8<link rel="up" href="Stdio.html#Stdio" title="Stdio"> 9<link rel="prev" href="fwide.html#fwide" title="fwide"> 10<link rel="next" href="getc.html#getc" title="getc"> 11<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 12<meta http-equiv="Content-Style-Type" content="text/css"> 13<style type="text/css"><!-- 14 pre.display { font-family:inherit } 15 pre.format { font-family:inherit } 16 pre.smalldisplay { font-family:inherit; font-size:smaller } 17 pre.smallformat { font-family:inherit; font-size:smaller } 18 pre.smallexample { font-size:smaller } 19 pre.smalllisp { font-size:smaller } 20 span.sc { font-variant:small-caps } 21 span.roman { font-family:serif; font-weight:normal; } 22 span.sansserif { font-family:sans-serif; font-weight:normal; } 23--></style> 24<link rel="stylesheet" type="text/css" href="../cs.css"> 25</head> 26<body> 27<div class="node"> 28<a name="fwrite"></a> 29<p> 30Next: <a rel="next" accesskey="n" href="getc.html#getc">getc</a>, 31Previous: <a rel="previous" accesskey="p" href="fwide.html#fwide">fwide</a>, 32Up: <a rel="up" accesskey="u" href="Stdio.html#Stdio">Stdio</a> 33<hr> 34</div> 35 36<h3 class="section">4.31 <code>fwrite</code>—write array elements</h3> 37 38<p><a name="index-fwrite-212"></a><a name="index-g_t_005ffwrite_005fr-213"></a><strong>Synopsis</strong> 39<pre class="example"> #include <stdio.h> 40 size_t fwrite(const void *<var>buf</var>, size_t <var>size</var>, 41 size_t <var>count</var>, FILE *<var>fp</var>); 42 43 #include <stdio.h> 44 size_t _fwrite_r(struct _reent *<var>ptr</var>, const void *<var>buf</var>, size_t <var>size</var>, 45 size_t <var>count</var>, FILE *<var>fp</var>); 46 47</pre> 48 <p><strong>Description</strong><br> 49<code>fwrite</code> attempts to copy, starting from the memory location 50<var>buf</var>, <var>count</var> elements (each of size <var>size</var>) into the file or 51stream identified by <var>fp</var>. <code>fwrite</code> may copy fewer elements than 52<var>count</var> if an error intervenes. 53 54 <p><code>fwrite</code> also advances the file position indicator (if any) for 55<var>fp</var> by the number of <em>characters</em> actually written. 56 57 <p><code>_fwrite_r</code> is simply the reentrant version of <code>fwrite</code> that 58takes an additional reentrant structure argument: <var>ptr</var>. 59 60 <p><br> 61<strong>Returns</strong><br> 62If <code>fwrite</code> succeeds in writing all the elements you specify, the 63result is the same as the argument <var>count</var>. In any event, the 64result is the number of complete elements that <code>fwrite</code> copied to 65the file. 66 67 <p><br> 68<strong>Portability</strong><br> 69ANSI C requires <code>fwrite</code>. 70 71 <p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>, 72<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>. 73 74 <p><br> 75 76 </body></html> 77 78