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114 lines
4.9 KiB
HTML
114 lines
4.9 KiB
HTML
4 years ago
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<title>ecvtbuf (The Red Hat newlib C Library)</title>
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<meta name="description" content="ecvtbuf (The Red Hat newlib C Library)">
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<link href="Document-Index.html#Document-Index" rel="index" title="Document Index">
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<link href="Document-Index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Stdlib.html#Stdlib" rel="up" title="Stdlib">
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<link href="_005f_005fenv_005flock.html#g_t_005f_005fenv_005flock" rel="next" title="__env_lock">
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<body lang="en">
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<a name="ecvtbuf"></a>
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<div class="header">
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<p>
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Next: <a href="_005f_005fenv_005flock.html#g_t_005f_005fenv_005flock" accesskey="n" rel="next">__env_lock</a>, Previous: <a href="gcvt.html#gcvt" accesskey="p" rel="prev">gcvt</a>, Up: <a href="Stdlib.html#Stdlib" accesskey="u" rel="up">Stdlib</a> [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="ecvtbuf_002c-fcvtbuf_002d_002d_002ddouble-or-float-to-string"></a>
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<h3 class="section">2.15 <code>ecvtbuf</code>, <code>fcvtbuf</code>—double or float to string</h3>
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<a name="index-ecvtbuf"></a>
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<a name="index-fcvtbuf"></a>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">#include <stdio.h>
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char *ecvtbuf(double <var>val</var>, int <var>chars</var>, int *<var>decpt</var>,
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int *<var>sgn</var>, char *<var>buf</var>);
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char *fcvtbuf(double <var>val</var>, int <var>decimals</var>, int *<var>decpt</var>,
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int *<var>sgn</var>, char *<var>buf</var>);
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</pre></div>
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<p><strong>Description</strong><br>
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<code>ecvtbuf</code> and <code>fcvtbuf</code> produce (null-terminated) strings
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of digits representating the <code>double</code> number <var>val</var>.
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</p>
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<p>The only difference between <code>ecvtbuf</code> and <code>fcvtbuf</code> is the
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interpretation of the second argument (<var>chars</var> or
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<var>decimals</var>). For <code>ecvtbuf</code>, the second argument <var>chars</var>
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specifies the total number of characters to write (which is
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also the number of significant digits in the formatted string,
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since these two functions write only digits). For <code>fcvtbuf</code>,
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the second argument <var>decimals</var> specifies the number of
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characters to write after the decimal point; all digits for
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the integer part of <var>val</var> are always included.
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</p>
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<p>Since <code>ecvtbuf</code> and <code>fcvtbuf</code> write only digits in the
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output string, they record the location of the decimal point
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in <code>*<var>decpt</var></code>, and the sign of the number in <code>*<var>sgn</var></code>.
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After formatting a number, <code>*<var>decpt</var></code> contains the number
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of digits to the left of the decimal point. <code>*<var>sgn</var></code>
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contains <code>0</code> if the number is positive, and <code>1</code> if it is
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negative. For both functions, you supply a pointer <var>buf</var> to
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an area of memory to hold the converted string.
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</p>
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<br>
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<p><strong>Returns</strong><br>
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Both functions return a pointer to <var>buf</var>, the string
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containing a character representation of <var>val</var>.
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</p>
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<br>
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<p><strong>Portability</strong><br>
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Neither function is ANSI C.
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</p>
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<p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>,
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<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>.
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</p>
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<br>
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</body>
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</html>
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