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<a name="ecvt_002c-ecvtf_002c-fcvt_002c-fcvtf_002d_002d_002ddouble-or-float-to-string"></a>
<h3 class="section">2.13 <code>ecvt</code>, <code>ecvtf</code>, <code>fcvt</code>, <code>fcvtf</code>&mdash;double or float to string</h3>
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<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdlib.h&gt;

char *ecvt(double <var>val</var>, int <var>chars</var>, int *<var>decpt</var>, int *<var>sgn</var>);
char *ecvtf(float <var>val</var>, int <var>chars</var>, int *<var>decpt</var>, int *<var>sgn</var>);

char *fcvt(double <var>val</var>, int <var>decimals</var>, 
    int *<var>decpt</var>, int *<var>sgn</var>);
char *fcvtf(float <var>val</var>, int <var>decimals</var>, 
    int *<var>decpt</var>, int *<var>sgn</var>);

</pre></div>
<p><strong>Description</strong><br>
<code>ecvt</code> and <code>fcvt</code> produce (null-terminated) strings of digits
representating the <code>double</code> number <var>val</var>.
<code>ecvtf</code> and <code>fcvtf</code> produce the corresponding character
representations of <code>float</code> numbers.
</p>
<p>(The <code>stdlib</code> functions <code>ecvtbuf</code> and <code>fcvtbuf</code> are reentrant
versions of <code>ecvt</code> and <code>fcvt</code>.)
</p>
<p>The only difference between <code>ecvt</code> and <code>fcvt</code> is the
interpretation of the second argument (<var>chars</var> or <var>decimals</var>).
For <code>ecvt</code>, the second argument <var>chars</var> specifies the total number
of characters to write (which is also the number of significant digits
in the formatted string, since these two functions write only digits).
For <code>fcvt</code>, the second argument <var>decimals</var> specifies the number of
characters to write after the decimal point; all digits for the integer
part of <var>val</var> are always included.
</p>
<p>Since <code>ecvt</code> and <code>fcvt</code> write only digits in the output string,
they record the location of the decimal point in <code>*<var>decpt</var></code>, and
the sign of the number in <code>*<var>sgn</var></code>.  After formatting a number,
<code>*<var>decpt</var></code> contains the number of digits to the left of the
decimal point.  <code>*<var>sgn</var></code> contains <code>0</code> if the number is positive,
and <code>1</code> if it is negative.
</p>
<br>
<p><strong>Returns</strong><br>
All four functions return a pointer to the new string containing a
character representation of <var>val</var>.
</p>
<br>
<p><strong>Portability</strong><br>
None of these functions are ANSI C.
</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>.
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