1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Standard Integer Types</title> 5<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Boost.Config"> 8<link rel="up" href="../index.html" title="Boost.Config"> 9<link rel="prev" href="build_config.html" title="Build Time Configuration"> 10<link rel="next" href="guidelines_for_boost_authors.html" title="Guidelines for Boost Authors"> 11</head> 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> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="build_config.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="guidelines_for_boost_authors.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 27<a name="boost_config.cstdint"></a><a class="link" href="cstdint.html" title="Standard Integer Types">Standard Integer Types</a> 28</h2></div></div></div> 29<div class="toc"><dl class="toc"> 30<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.overview">Overview</a></span></dt> 31<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.rationale">Rationale</a></span></dt> 32<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.ce"><span class="emphasis"><em>Caveat emptor</em></span></a></span></dt> 33<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.exact_width_integer_types">Exact-width 34 integer types</a></span></dt> 35<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.minimum_width_integer_types">Minimum-width 36 integer types</a></span></dt> 37<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.fastest_minimum_width_integer_types">Fastest 38 minimum-width integer types</a></span></dt> 39<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.greatest_width_integer_types">Greatest-width 40 integer types</a></span></dt> 41<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.integer_constant_macros">Integer 42 Constant Macros</a></span></dt> 43<dt><span class="section"><a href="cstdint.html#boost_config.cstdint.intptr">Integers for Storing Pointers</a></span></dt> 44</dl></div> 45<div class="section"> 46<div class="titlepage"><div><div><h3 class="title"> 47<a name="boost_config.cstdint.overview"></a><a class="link" href="cstdint.html#boost_config.cstdint.overview" title="Overview">Overview</a> 48</h3></div></div></div> 49<p> 50 The header <code class="literal"><a href="../../../../../boost/cstdint.hpp" target="_top"><boost/cstdint.hpp></a></code> 51 provides the typedef's useful for writing portable code that requires certain 52 integer widths. All typedef's are in namespace boost. 53 </p> 54<p> 55 The specifications for these types are based on the ISO/IEC 9899:1999 C Language 56 standard header <stdint.h>. The 64-bit types required by the C standard 57 are <span class="emphasis"><em>not required</em></span> in the boost header, and may not be 58 supplied for all platforms/compilers, because <code class="literal">long long</code> 59 is not [yet] included in the C++ standard. 60 </p> 61<p> 62 See <a href="../../../test/cstdint_test.cpp" target="_top">cstdint_test.cpp</a> for 63 a test program. 64 </p> 65</div> 66<div class="section"> 67<div class="titlepage"><div><div><h3 class="title"> 68<a name="boost_config.cstdint.rationale"></a><a class="link" href="cstdint.html#boost_config.cstdint.rationale" title="Rationale">Rationale</a> 69</h3></div></div></div> 70<p> 71 The organization of the Boost.Integer headers and classes is designed to 72 take advantage of <stdint.h> types from the 1999 C standard without 73 causing undefined behavior in terms of the 1998 C++ standard. The header 74 <boost/cstdint.hpp> makes the standard integer types safely available 75 in namespace <code class="literal">boost</code> without placing any names in namespace 76 <code class="literal">std</code>. The intension is to complement rather than compete 77 with the C++ Standard Library. Should some future C++ standard include <stdint.h> 78 and <cstdint>, then <boost/cstdint.hpp> will continue to function, 79 but will become redundant and may be safely deprecated. 80 </p> 81<p> 82 Because these are boost headers, their names conform to boost header naming 83 conventions rather than C++ Standard Library header naming conventions. 84 </p> 85</div> 86<div class="section"> 87<div class="titlepage"><div><div><h3 class="title"> 88<a name="boost_config.cstdint.ce"></a><a class="link" href="cstdint.html#boost_config.cstdint.ce" title="Caveat emptor"><span class="emphasis"><em>Caveat emptor</em></span></a> 89</h3></div></div></div> 90<p> 91 As an implementation artifact, certain C <limits.h> macro names may 92 possibly be visible to users of <boost/cstdint.hpp>. Don't use these 93 macros; they are not part of any Boost-specified interface. Use <code class="literal">boost::integer_traits<></code> 94 or <code class="literal">std::numeric_limits<></code> instead. 95 </p> 96<p> 97 As another implementation artifact, certain C <stdint.h> typedef names 98 may possibly be visible in the global namespace to users of <boost/cstdint.hpp>. 99 Don't use these names, they are not part of any Boost-specified interface. 100 Use the respective names in namespace <code class="literal">boost</code> instead. 101 </p> 102</div> 103<div class="section"> 104<div class="titlepage"><div><div><h3 class="title"> 105<a name="boost_config.cstdint.exact_width_integer_types"></a><a class="link" href="cstdint.html#boost_config.cstdint.exact_width_integer_types" title="Exact-width integer types">Exact-width 106 integer types</a> 107</h3></div></div></div> 108<p> 109 The typedef <code class="literal">int#_t</code>, with # replaced by the width, designates 110 a signed integer type of exactly # bits; for example <code class="literal">int8_t</code> 111 denotes an 8-bit signed integer type. Similarly, the typedef <code class="literal">uint#_t</code> 112 designates an unsigned integer type of exactly # bits. 113 </p> 114<p> 115 These types are optional. However, if a platform supports integer types with 116 widths of 8, 16, 32, 64, or any combination thereof, then <boost/cstdint.hpp> 117 does provide the corresponding typedefs. 118 </p> 119<p> 120 The absence of int64_t and uint64_t is indicated by the macro <code class="computeroutput"><span class="identifier">BOOST_NO_INT64_T</span></code>. 121 </p> 122</div> 123<div class="section"> 124<div class="titlepage"><div><div><h3 class="title"> 125<a name="boost_config.cstdint.minimum_width_integer_types"></a><a class="link" href="cstdint.html#boost_config.cstdint.minimum_width_integer_types" title="Minimum-width integer types">Minimum-width 126 integer types</a> 127</h3></div></div></div> 128<p> 129 The typedef <code class="literal">int_least#_t</code>, with # replaced by the width, 130 designates a signed integer type with a width of at least # bits, such that 131 no signed integer type with lesser size has at least the specified width. 132 Thus, <code class="literal">int_least32_t</code> denotes the smallest signed integer 133 type with a width of at least 32 bits. Similarly, the typedef name <code class="literal">uint_least#_t</code> 134 designates an unsigned integer type with a width of at least # bits, such 135 that no unsigned integer type with lesser size has at least the specified 136 width. 137 </p> 138<p> 139 The following minimum-width integer types are provided for all platforms: 140 </p> 141<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 142<li class="listitem"> 143 <code class="literal">int_least8_t</code> 144 </li> 145<li class="listitem"> 146 <code class="literal">int_least16_t</code> 147 </li> 148<li class="listitem"> 149 <code class="literal">int_least32_t</code> 150 </li> 151<li class="listitem"> 152 <code class="literal">uint_least8_t</code> 153 </li> 154<li class="listitem"> 155 <code class="literal">uint_least16_t</code> 156 </li> 157<li class="listitem"> 158 <code class="literal">uint_least32_t</code> 159 </li> 160</ul></div> 161<p> 162 The following types are available only if, after including <boost/cstdint.hpp>, 163 the macro BOOST_NO_INT64_T is not defined: 164 </p> 165<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 166<li class="listitem"> 167 <code class="literal">int_least64_t</code> 168 </li> 169<li class="listitem"> 170 <code class="literal">uint_least64_t</code> 171 </li> 172</ul></div> 173<p> 174 All other minimum-width integer types are optional. 175 </p> 176</div> 177<div class="section"> 178<div class="titlepage"><div><div><h3 class="title"> 179<a name="boost_config.cstdint.fastest_minimum_width_integer_types"></a><a class="link" href="cstdint.html#boost_config.cstdint.fastest_minimum_width_integer_types" title="Fastest minimum-width integer types">Fastest 180 minimum-width integer types</a> 181</h3></div></div></div> 182<p> 183 The typedef <code class="literal">int_fast#_t</code>, with # replaced by the width, 184 designates the fastest signed integer type with a width of at least # bits. 185 Similarly, the typedef name <code class="literal">uint_fast#_t</code> designates the 186 fastest unsigned integer type with a width of at least # bits. 187 </p> 188<p> 189 There is no guarantee that these types are fastest for all purposes. In any 190 case, however, they satisfy the signedness and width requirements. 191 </p> 192<p> 193 The following fastest minimum-width integer types are provided for all platforms: 194 </p> 195<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 196<li class="listitem"> 197 <code class="literal">int_fast8_t</code> 198 </li> 199<li class="listitem"> 200 <code class="literal">int_fast16_t</code> 201 </li> 202<li class="listitem"> 203 <code class="literal">int_fast32_t</code> 204 </li> 205<li class="listitem"> 206 <code class="literal">uint_fast8_t</code> 207 </li> 208<li class="listitem"> 209 <code class="literal">uint_fast16_t</code> 210 </li> 211<li class="listitem"> 212 <code class="literal">uint_fast32_t</code> 213 </li> 214</ul></div> 215<p> 216 The following types are available only if, after including <boost/cstdint.hpp>, 217 the macro BOOST_NO_INT64_T is not defined: 218 </p> 219<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 220<li class="listitem"> 221 <code class="literal">int_fast64_t</code> 222 </li> 223<li class="listitem"> 224 <code class="literal">uint_fast64_t</code> 225 </li> 226</ul></div> 227<p> 228 All other fastest minimum-width integer types are optional. 229 </p> 230</div> 231<div class="section"> 232<div class="titlepage"><div><div><h3 class="title"> 233<a name="boost_config.cstdint.greatest_width_integer_types"></a><a class="link" href="cstdint.html#boost_config.cstdint.greatest_width_integer_types" title="Greatest-width integer types">Greatest-width 234 integer types</a> 235</h3></div></div></div> 236<p> 237 The typedef <code class="literal">intmax_t </code>designates a signed integer type 238 capable of representing any value of any signed integer type. 239 </p> 240<p> 241 The typedef <code class="literal">uintmax_t</code> designates an unsigned integer type 242 capable of representing any value of any unsigned integer type. 243 </p> 244<p> 245 These types are provided for all platforms. 246 </p> 247</div> 248<div class="section"> 249<div class="titlepage"><div><div><h3 class="title"> 250<a name="boost_config.cstdint.integer_constant_macros"></a><a class="link" href="cstdint.html#boost_config.cstdint.integer_constant_macros" title="Integer Constant Macros">Integer 251 Constant Macros</a> 252</h3></div></div></div> 253<p> 254 The following macros are always defined after inclusion of this header, these 255 allow integer constants of at least the specified width to be declared: INT8_C, 256 UINT8_C, INT16_C, UINT16_C, INT32_C, UINT32_C, INTMAX_C, UINTMAX_C. 257 </p> 258<p> 259 The macros INT64_C and UINT64_C are also defined if the the macro BOOST_NO_INT64_T 260 is not defined. 261 </p> 262<p> 263 The C99 macro __STDC_CONSTANT_MACROS is also defined as an artifact of the 264 implementation. 265 </p> 266<p> 267 For example: 268 </p> 269<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cstdint</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 270 271<span class="comment">// Here the constant 0x1FFFFFFFF has the correct suffix applied:</span> 272<span class="keyword">static</span> <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">uint64_t</span> <span class="identifier">c</span> <span class="special">=</span> <span class="identifier">INT64_C</span><span class="special">(</span><span class="number">0</span><span class="identifier">x1FFFFFFFF</span><span class="special">);</span> 273</pre> 274</div> 275<div class="section"> 276<div class="titlepage"><div><div><h3 class="title"> 277<a name="boost_config.cstdint.intptr"></a><a class="link" href="cstdint.html#boost_config.cstdint.intptr" title="Integers for Storing Pointers">Integers for Storing Pointers</a> 278</h3></div></div></div> 279<p> 280 The typedefs <code class="literal">intptr_t</code> and <code class="literal">uintptr_t</code> 281 defined signed and unsigned integers respectively each capable of storing 282 a pointer. The macro <code class="literal">BOOST_HAS_INTPTR_T</code> is set when these 283 types are available. 284 </p> 285</div> 286</div> 287<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 288<td align="left"></td> 289<td align="right"><div class="copyright-footer">Copyright © 2001-2007 Beman Dawes, Vesa Karvonen, John 290 Maddock<p> 291 Distributed under the Boost Software License, Version 1.0. (See accompanying 292 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>) 293 </p> 294</div></td> 295</tr></table> 296<hr> 297<div class="spirit-nav"> 298<a accesskey="p" href="build_config.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="guidelines_for_boost_authors.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 299</div> 300</body> 301</html> 302
