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<a name="wcstod_002c-wcstof_002c-wcstold_002c-wcstod_005fl_002c-wcstof_005fl_002c-wcstold_005fl_002d_002d_002dwide-char-string-to-double-or-float"></a>
<h3 class="section">2.43 <code>wcstod</code>, <code>wcstof</code>, <code>wcstold</code>, <code>wcstod_l</code>, <code>wcstof_l</code>, <code>wcstold_l</code>&mdash;wide char string to double or float</h3>
<a name="index-wcstod"></a>
<a name="index-wcstof"></a>
<a name="index-wcstold"></a>
<a name="index-wcstod_005fl"></a>
<a name="index-wcstof_005fl"></a>
<a name="index-wcstold_005fl"></a>
<a name="index-_005fwcstod_005fr"></a>
<a name="index-_005fwcstof_005fr"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdlib.h&gt;
double wcstod(const wchar_t *__restrict <var>str</var>,
    wchar_t **__restrict <var>tail</var>);
float wcstof(const wchar_t *__restrict <var>str</var>,
    wchar_t **__restrict <var>tail</var>);
long double wcstold(const wchar_t *__restrict <var>str</var>,
    wchar_t **__restrict <var>tail</var>);

#include &lt;stdlib.h&gt;
double wcstod_l(const wchar_t *__restrict <var>str</var>,
    wchar_t **__restrict <var>tail</var>, locale_t <var>locale</var>);
float wcstof_l(const wchar_t *__restrict <var>str</var>,
    wchar_t **__restrict <var>tail</var>, locale_t <var>locale</var>);
long double wcstold_l(const wchar_t *__restrict <var>str</var>,
    wchar_t **__restrict <var>tail</var>,
    locale_t <var>locale</var>);

double _wcstod_r(void *<var>reent</var>,
    const wchar_t *<var>str</var>, wchar_t **<var>tail</var>);
float _wcstof_r(void *<var>reent</var>,
    const wchar_t *<var>str</var>, wchar_t **<var>tail</var>);

</pre></div>
<p><strong>Description</strong><br>
<code>wcstod</code>, <code>wcstof</code>, <code>wcstold</code> parse the wide-character string
<var>str</var>, producing a substring which can be converted to a double,
float, or long double value.  The substring converted is the longest
initial subsequence of <var>str</var>, beginning with the first non-whitespace
character, that has one of these formats:
</p><div class="smallexample">
<pre class="smallexample">[+|-]<var>digits</var>[.[<var>digits</var>]][(e|E)[+|-]<var>digits</var>]
[+|-].<var>digits</var>[(e|E)[+|-]<var>digits</var>]
[+|-](i|I)(n|N)(f|F)[(i|I)(n|N)(i|I)(t|T)(y|Y)]
[+|-](n|N)(a|A)(n|N)[&lt;(&gt;[<var>hexdigits</var>]&lt;)&gt;]
[+|-]0(x|X)<var>hexdigits</var>[.[<var>hexdigits</var>]][(p|P)[+|-]<var>digits</var>]
[+|-]0(x|X).<var>hexdigits</var>[(p|P)[+|-]<var>digits</var>]
</pre></div>
<p>The substring contains no characters if <var>str</var> is empty, consists
entirely of whitespace, or if the first non-whitespace
character is something other than <code>+</code>, <code>-</code>, <code>.</code>, or a
digit, and cannot be parsed as infinity or NaN. If the platform
does not support NaN, then NaN is treated as an empty substring.
If the substring is empty, no conversion is done, and
the value of <var>str</var> is stored in <code>*<var>tail</var></code>.  Otherwise,
the substring is converted, and a pointer to the final string
(which will contain at least the terminating null character of
<var>str</var>) is stored in <code>*<var>tail</var></code>.  If you want no
assignment to <code>*<var>tail</var></code>, pass a null pointer as <var>tail</var>.
</p>
<p>This implementation returns the nearest machine number to the
input decimal string.  Ties are broken by using the IEEE
round-even rule.  However, <code>wcstof</code> is currently subject to
double rounding errors.
</p>
<p><code>wcstod_l</code>, <code>wcstof_l</code>, <code>wcstold_l</code> are like <code>wcstod</code>,
<code>wcstof</code>, <code>wcstold</code> but perform the conversion based on the
locale specified by the locale object locale.  If <var>locale</var> is
LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is
undefined.
</p>
<p>The alternate functions <code>_wcstod_r</code> and <code>_wcstof_r</code> are 
reentrant versions of <code>wcstod</code> and <code>wcstof</code>, respectively.
The extra argument <var>reent</var> is a pointer to a reentrancy structure.
</p>
<br>
<p><strong>Returns</strong><br>
Return the converted substring value, if any.  If
no conversion could be performed, 0 is returned.  If the
correct value is out of the range of representable values,
plus or minus <code>HUGE_VAL</code> is returned, and <code>ERANGE</code> is
stored in errno. If the correct value would cause underflow, 0
is returned and <code>ERANGE</code> is stored in errno.
</p>
<br>
<p><strong>Portability</strong><br>
<code>wcstod</code> is ANSI.
<code>wcstof</code>, <code>wcstold</code> are C99.
<code>wcstod_l</code>, <code>wcstof_l</code>, <code>wcstold_l</code> are GNU extensions.
</p>
<p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>,
<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>.
</p>
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