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<a name="mblen_002d_002d_002dminimal-multibyte-length-function"></a>
<h3 class="section">2.27 <code>mblen</code>&mdash;minimal multibyte length function</h3>
<a name="index-mblen"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdlib.h&gt;
int mblen(const char *<var>s</var>, size_t <var>n</var>);
</pre></div>
<p><strong>Description</strong><br>
When _MB_CAPABLE is not defined, this is a minimal ANSI-conforming
implementation of <code>mblen</code>. In this case, the
only &ldquo;multi-byte character sequences&rdquo; recognized are single bytes,
and thus <code>1</code> is returned unless <var>s</var> is the null pointer or
has a length of 0 or is the empty string.
</p>
<p>When _MB_CAPABLE is defined, this routine calls <code>_mbtowc_r</code> to perform
the conversion, passing a state variable to allow state dependent
decoding. The result is based on the locale setting which may
be restricted to a defined set of locales.
</p>
<br>
<p><strong>Returns</strong><br>
This implementation of <code>mblen</code> returns <code>0</code> if
<var>s</var> is <code>NULL</code> or the empty string; it returns <code>1</code> if not _MB_CAPABLE or
the character is a single-byte character; it returns <code>-1</code>
if the multi-byte character is invalid; otherwise it returns
the number of bytes in the multibyte character.
</p>
<br>
<p><strong>Portability</strong><br>
<code>mblen</code> is required in the ANSI C standard. However, the precise
effects vary with the locale.
</p>
<p><code>mblen</code> requires no supporting OS subroutines.
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