1<html lang="en"> 2<head> 3<title>gvcvt - 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="_005f_005fenv_005flock.html#g_t_005f_005fenv_005flock" title="__env_lock"> 10<link rel="next" href="exit.html#exit" title="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="gvcvt"></a> 29<p> 30Next: <a rel="next" accesskey="n" href="exit.html#exit">exit</a>, 31Previous: <a rel="previous" accesskey="p" href="_005f_005fenv_005flock.html#g_t_005f_005fenv_005flock">__env_lock</a>, 32Up: <a rel="up" accesskey="u" href="Stdlib.html#Stdlib">Stdlib</a> 33<hr> 34</div> 35 36<h3 class="section">2.14 <code>gvcvt</code>, <code>gcvtf</code>—format double or float as string</h3> 37 38<p><a name="index-gcvt-24"></a><a name="index-gcvtf-25"></a><strong>Synopsis</strong> 39<pre class="example"> #include <stdlib.h> 40 41 char *gcvt(double <var>val</var>, int <var>precision</var>, char *<var>buf</var>); 42 char *gcvtf(float <var>val</var>, int <var>precision</var>, char *<var>buf</var>); 43 44</pre> 45 <p><strong>Description</strong><br> 46<code>gcvt</code> writes a fully formatted number as a null-terminated 47string in the buffer <code>*</code><var>buf</var>. <code>gdvtf</code> produces corresponding 48character representations of <code>float</code> numbers. 49 50 <p><code>gcvt</code> uses the same rules as the <code>printf</code> format 51`<code>%.</code><var>precision</var><code>g</code>'—only negative values are signed (with 52`<code>-</code>'), and either exponential or ordinary decimal-fraction format 53is chosen depending on the number of significant digits (specified by 54<var>precision</var>). 55 56 <p><br> 57<strong>Returns</strong><br> 58The result is a pointer to the formatted representation of <var>val</var> 59(the same as the argument <var>buf</var>). 60 61 <p><br> 62<strong>Portability</strong><br> 63Neither function is ANSI C. 64 65 <p>Supporting OS subroutines required: <code>close</code>, <code>fstat</code>, <code>isatty</code>, 66<code>lseek</code>, <code>read</code>, <code>sbrk</code>, <code>write</code>. 67 68 <p><br> 69 70 </body></html> 71 72