1<html lang="en"> 2<head> 3<title>mbtowc - 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="Stdlib.html#Stdlib" title="Stdlib"> 9<link rel="prev" href="mblen.html#mblen" title="mblen"> 10<link rel="next" href="on_005fexit.html#on_005fexit" title="on_exit"> 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="mbtowc"></a> 29<p> 30Next: <a rel="next" accesskey="n" href="on_005fexit.html#on_005fexit">on_exit</a>, 31Previous: <a rel="previous" accesskey="p" href="mblen.html#mblen">mblen</a>, 32Up: <a rel="up" accesskey="u" href="Stdlib.html#Stdlib">Stdlib</a> 33<hr> 34</div> 35 36<h3 class="section">2.29 <code>mbtowc</code>—minimal multibyte to wide char converter</h3> 37 38<p><a name="index-mbtowc-63"></a><strong>Synopsis</strong> 39<pre class="example"> #include <stdlib.h> 40 int mbtowc(wchar_t *<var>pwc</var>, const char *<var>s</var>, size_t <var>n</var>); 41 42</pre> 43 <p><strong>Description</strong><br> 44When _MB_CAPABLE is not defined, this is a minimal ANSI-conforming 45implementation of <code>mbtowc</code>. In this case, 46only “multi-byte character sequences” recognized are single bytes, 47and they are “converted” to themselves. 48Each call to <code>mbtowc</code> copies one character from <code>*</code><var>s</var> to 49<code>*</code><var>pwc</var>, unless <var>s</var> is a null pointer. The argument n 50is ignored. 51 52 <p>When _MB_CAPABLE is defined, this routine calls <code>_mbtowc_r</code> to perform 53the conversion, passing a state variable to allow state dependent 54decoding. The result is based on the locale setting which may 55be restricted to a defined set of locales. 56 57 <p><br> 58<strong>Returns</strong><br> 59This implementation of <code>mbtowc</code> returns <code>0</code> if 60<var>s</var> is <code>NULL</code> or is the empty string; 61it returns <code>1</code> if not _MB_CAPABLE or 62the character is a single-byte character; it returns <code>-1</code> 63if n is <code>0</code> or the multi-byte character is invalid; 64otherwise it returns the number of bytes in the multibyte character. 65If the return value is -1, no changes are made to the <code>pwc</code> 66output string. If the input is the empty string, a wchar_t nul 67is placed in the output string and 0 is returned. If the input 68has a length of 0, no changes are made to the <code>pwc</code> output string. 69 70 <p><br> 71<strong>Portability</strong><br> 72<code>mbtowc</code> is required in the ANSI C standard. However, the precise 73effects vary with the locale. 74 75 <p><code>mbtowc</code> requires no supporting OS subroutines. 76 77 <p><br> 78 79 </body></html> 80 81