3 <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
4 <title>Finding the Next Smaller Representable Value (float_prior)</title>
5 <link rel="stylesheet" href="../../math.css" type="text/css">
6 <meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
7 <link rel="home" href="../../index.html" title="Math Toolkit 2.5.2">
8 <link rel="up" href="../next_float.html" title="Floating-Point Representation Distance (ULP), and Finding Adjacent Floating-Point Values">
9 <link rel="prev" href="float_next.html" title="Finding the Next Greater Representable Value (float_next)">
10 <link rel="next" href="float_distance.html" title="Calculating the Representation Distance Between Two floating-point Values (ULP) float_distance">
12 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
13 <table cellpadding="2" width="100%"><tr>
14 <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td>
15 <td align="center"><a href="../../../../../../index.html">Home</a></td>
16 <td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td>
17 <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
18 <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
19 <td align="center"><a href="../../../../../../more/index.htm">More</a></td>
22 <div class="spirit-nav">
23 <a accesskey="p" href="float_next.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../next_float.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="float_distance.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
26 <div class="titlepage"><div><div><h3 class="title">
27 <a name="math_toolkit.next_float.float_prior"></a><a class="link" href="float_prior.html" title="Finding the Next Smaller Representable Value (float_prior)">Finding the Next
28 Smaller Representable Value (float_prior)</a>
29 </h3></div></div></div>
31 <a name="math_toolkit.next_float.float_prior.h0"></a>
32 <span class="phrase"><a name="math_toolkit.next_float.float_prior.synopsis"></a></span><a class="link" href="float_prior.html#math_toolkit.next_float.float_prior.synopsis">Synopsis</a>
34 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">math</span><span class="special">/</span><span class="identifier">special_functions</span><span class="special">/</span><span class="identifier">next</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
36 <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">math</span><span class="special">{</span>
38 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">FPT</span><span class="special">></span>
39 <span class="identifier">FPT</span> <span class="identifier">float_prior</span><span class="special">(</span><span class="identifier">FPT</span> <span class="identifier">val</span><span class="special">);</span>
41 <span class="special">}}</span> <span class="comment">// namespaces</span>
44 <a name="math_toolkit.next_float.float_prior.h1"></a>
45 <span class="phrase"><a name="math_toolkit.next_float.float_prior.description_float_prior"></a></span><a class="link" href="float_prior.html#math_toolkit.next_float.float_prior.description_float_prior">Description
49 Returns the next representable value which is less than <span class="emphasis"><em>x</em></span>.
50 If <span class="emphasis"><em>x</em></span> is non-finite then returns the result of a <a class="link" href="../error_handling.html#math_toolkit.error_handling.domain_error">domain_error</a>. If
51 there is no such value less than <span class="emphasis"><em>x</em></span> then returns an
52 <a class="link" href="../error_handling.html#math_toolkit.error_handling.overflow_error">overflow_error</a>.
55 Has the same effect as
57 <pre class="programlisting"><span class="identifier">nextafter</span><span class="special">(</span><span class="identifier">val</span><span class="special">,</span> <span class="special">-(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special"><</span><span class="identifier">FPT</span><span class="special">>::</span><span class="identifier">max</span><span class="special">)());</span> <span class="comment">// Note most negative value -max.</span>
60 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
61 <td align="left"></td>
62 <td align="right"><div class="copyright-footer">Copyright © 2006-2010, 2012-2014 Nikhar Agrawal,
63 Anton Bikineev, Paul A. Bristow, Marco Guazzone, Christopher Kormanyos, Hubert
64 Holin, Bruno Lalande, John Maddock, Jeremy Murphy, Johan Råde, Gautam Sewani,
65 Benjamin Sobotta, Thijs van den Berg, Daryle Walker and Xiaogang Zhang<p>
66 Distributed under the Boost Software License, Version 1.0. (See accompanying
67 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
72 <div class="spirit-nav">
73 <a accesskey="p" href="float_next.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../next_float.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="float_distance.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>