216 lines
8.5 KiB
HTML
216 lines
8.5 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
|
<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
|
|
<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
|
|
<title>tan</title>
|
|
</head>
|
|
<body bgcolor="white">
|
|
<script type="text/javascript" language="JavaScript" src="../jscript/codes.js">
|
|
</script>
|
|
|
|
<basefont size="3"> <a name="tan"></a> <a name="tag_03_758"></a><!-- tan -->
|
|
<!--header start-->
|
|
<center><font size="2">The Open Group Base Specifications Issue 6<br>
|
|
IEEE Std 1003.1-2001<br>
|
|
Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
|
|
|
|
<!--header end-->
|
|
<hr size="2" noshade>
|
|
<h4><a name="tag_03_758_01"></a>NAME</h4>
|
|
|
|
<blockquote>tan, tanf, tanl - tangent function</blockquote>
|
|
|
|
<h4><a name="tag_03_758_02"></a>SYNOPSIS</h4>
|
|
|
|
<blockquote class="synopsis">
|
|
<p><code><tt>#include <<a href="../basedefs/math.h.html">math.h</a>><br>
|
|
<br>
|
|
double tan(double</tt> <i>x</i><tt>);<br>
|
|
float tanf(float</tt> <i>x</i><tt>);<br>
|
|
long double tanl(long double</tt> <i>x</i><tt>);<br>
|
|
</tt></code></p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_03"></a>DESCRIPTION</h4>
|
|
|
|
<blockquote>
|
|
<div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"
|
|
border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the
|
|
requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to
|
|
the ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div>
|
|
|
|
<p>These functions shall compute the tangent of their argument <i>x</i>, measured in radians.</p>
|
|
|
|
<p>An application wishing to check for error situations should set <i>errno</i> to zero and call
|
|
<i>feclearexcept</i>(FE_ALL_EXCEPT) before calling these functions. On return, if <i>errno</i> is non-zero or
|
|
<i>fetestexcept</i>(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_04"></a>RETURN VALUE</h4>
|
|
|
|
<blockquote>
|
|
<p>Upon successful completion, these functions shall return the tangent of <i>x</i>.</p>
|
|
|
|
<p>If the correct value would cause underflow, and is not representable, a range error may occur, and <sup>[<a href=
|
|
"javascript:open_code('MX')">MX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> either 0.0 (if
|
|
supported), or <img src="../images/opt-end.gif" alt="[Option End]" border="0"> an implementation-defined value shall be
|
|
returned.</p>
|
|
|
|
<p><sup>[<a href="javascript:open_code('MX')">MX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> If
|
|
<i>x</i> is NaN, a NaN shall be returned.</p>
|
|
|
|
<p>If <i>x</i> is ±0, <i>x</i> shall be returned.</p>
|
|
|
|
<p>If <i>x</i> is subnormal, a range error may occur and <i>x</i> should be returned.</p>
|
|
|
|
<p>If <i>x</i> is ±Inf, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value
|
|
shall be returned.</p>
|
|
|
|
<p>If the correct value would cause underflow, and is representable, a range error may occur and the correct value shall be
|
|
returned. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>
|
|
|
|
<p><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
|
|
If the correct value would cause overflow, a range error shall occur and <i>tan</i>(), <i>tanf</i>(), and <i>tanl</i>() shall
|
|
return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively. <img src="../images/opt-end.gif" alt="[Option End]"
|
|
border="0"></p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_05"></a>ERRORS</h4>
|
|
|
|
<blockquote>
|
|
<p>These functions shall fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>Domain Error</dt>
|
|
|
|
<dd><sup>[<a href="javascript:open_code('MX')">MX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
|
|
The value of <i>x</i> is ±Inf.
|
|
|
|
<p>If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then <i>errno</i> shall be set to [EDOM]. If the
|
|
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.
|
|
<img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>
|
|
</dd>
|
|
|
|
<dt>Range Error</dt>
|
|
|
|
<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
|
|
The result overflows
|
|
|
|
<p>If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then <i>errno</i> shall be set to [ERANGE]. If the
|
|
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised.
|
|
<img src="../images/opt-end.gif" alt="[Option End]" border="0"></p>
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>These functions may fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>Range Error</dt>
|
|
|
|
<dd>The result underflows, <sup>[<a href="javascript:open_code('MX')">MX</a>]</sup> <img src="../images/opt-start.gif" alt=
|
|
"[Option Start]" border="0"> or the value of <i>x</i> is subnormal. <img src="../images/opt-end.gif" alt="[Option End]"
|
|
border="0">
|
|
|
|
<p>If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then <i>errno</i> shall be set to [ERANGE]. If the
|
|
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be
|
|
raised.</p>
|
|
</dd>
|
|
</dl>
|
|
</blockquote>
|
|
|
|
<hr>
|
|
<div class="box"><em>The following sections are informative.</em></div>
|
|
|
|
<h4><a name="tag_03_758_06"></a>EXAMPLES</h4>
|
|
|
|
<blockquote>
|
|
<h5><a name="tag_03_758_06_01"></a>Taking the Tangent of a 45-Degree Angle</h5>
|
|
|
|
<pre>
|
|
<tt>#include <math.h>
|
|
...
|
|
double radians = 45.0 * M_PI / 180;
|
|
double result;
|
|
...
|
|
result = tan (radians);
|
|
</tt>
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_07"></a>APPLICATION USAGE</h4>
|
|
|
|
<blockquote>
|
|
<p>There are no known floating-point representations such that for a normal argument, <i>tan</i>( <i>x</i>) is either overflow or
|
|
underflow.</p>
|
|
|
|
<p>These functions may lose accuracy when their argument is near a multiple of <img src="../images/pi.gif" border="0">/2 or is far
|
|
from 0.0.</p>
|
|
|
|
<p>On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of
|
|
each other, but at least one of them must be non-zero.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_08"></a>RATIONALE</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_09"></a>FUTURE DIRECTIONS</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_10"></a>SEE ALSO</h4>
|
|
|
|
<blockquote>
|
|
<p><a href="atan.html"><i>atan</i>()</a> , <a href="feclearexcept.html"><i>feclearexcept</i>()</a> , <a href=
|
|
"fetestexcept.html"><i>fetestexcept</i>()</a> , <a href="isnan.html"><i>isnan</i>()</a> , the Base Definitions volume of
|
|
IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap04.html#tag_04_18">Section 4.18, Treatment of Error Conditions for
|
|
Mathematical Functions</a>, <a href="../basedefs/math.h.html"><i><math.h></i></a></p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_11"></a>CHANGE HISTORY</h4>
|
|
|
|
<blockquote>
|
|
<p>First released in Issue 1. Derived from Issue 1 of the SVID.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_12"></a>Issue 5</h4>
|
|
|
|
<blockquote>
|
|
<p>The last two paragraphs of the DESCRIPTION were included as APPLICATION USAGE notes in previous issues.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_758_13"></a>Issue 6</h4>
|
|
|
|
<blockquote>
|
|
<p>The <i>tanf</i>() and <i>tanl</i>() functions are added for alignment with the ISO/IEC 9899:1999 standard.</p>
|
|
|
|
<p>The DESCRIPTION, RETURN VALUE, ERRORS, and APPLICATION USAGE sections are revised to align with the ISO/IEC 9899:1999
|
|
standard.</p>
|
|
|
|
<p>IEC 60559:1989 standard floating-point extensions over the ISO/IEC 9899:1999 standard are marked.</p>
|
|
</blockquote>
|
|
|
|
<div class="box"><em>End of informative text.</em></div>
|
|
|
|
<hr>
|
|
<hr size="2" noshade>
|
|
<center><font size="2"><!--footer start-->
|
|
UNIX ® is a registered Trademark of The Open Group.<br>
|
|
POSIX ® is a registered Trademark of The IEEE.<br>
|
|
[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href=
|
|
"../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>
|
|
]</font></center>
|
|
|
|
<!--footer end-->
|
|
<hr size="2" noshade>
|
|
</body>
|
|
</html>
|
|
|