1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Choosing a Boost.Python Library Binary</title> 5<link rel="stylesheet" href="../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.Python"> 8<link rel="up" href="../building.html" title="Chapter 2. Building and Testing"> 9<link rel="prev" href="configuring_boost_build.html" title="Configuring Boost.Build"> 10<link rel="next" href="include_issues.html" title="#include Issues"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="" width="" height="" src="../images/boost.png"></td></tr></table> 14<hr> 15<div class="spirit-nav"> 16<a accesskey="p" href="configuring_boost_build.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../building.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="include_issues.html"><img src="../images/next.png" alt="Next"></a> 17</div> 18<div class="section"> 19<div class="titlepage"><div><div><h3 class="title"> 20<a name="building.choosing_a_boost_python_library_"></a><a class="link" href="choosing_a_boost_python_library_.html" title="Choosing a Boost.Python Library Binary">Choosing a 21 Boost.Python Library Binary</a> 22</h3></div></div></div> 23<div class="toc"><dl class="toc"> 24<dt><span class="section"><a href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_dynamic_binary">The 25 Dynamic Binary</a></span></dt> 26<dt><span class="section"><a href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_static_binary">The 27 Static Binary</a></span></dt> 28</dl></div> 29<p> 30 If—instead of letting Boost.Build construct and link with the right libraries 31 automatically—you choose to use a pre-built Boost.Python library, you'll 32 need to think about which one to link with. The Boost.Python binary comes 33 in both static and dynamic flavors. Take care to choose the right flavor 34 for your application. <a href="#ftn.building.choosing_a_boost_python_library_.f0" class="footnote" name="building.choosing_a_boost_python_library_.f0"><sup class="footnote">[3]</sup></a> 35 </p> 36<div class="section"> 37<div class="titlepage"><div><div><h4 class="title"> 38<a name="building.choosing_a_boost_python_library_.the_dynamic_binary"></a><a class="link" href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_dynamic_binary" title="The Dynamic Binary">The 39 Dynamic Binary</a> 40</h4></div></div></div> 41<p> 42 The dynamic library is the safest and most-versatile choice: 43 </p> 44<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 45<li class="listitem"> 46 A single copy of the library code is used by all extension modules 47 built with a given toolset. <a href="#ftn.building.choosing_a_boost_python_library_.the_dynamic_binary.f0" class="footnote" name="building.choosing_a_boost_python_library_.the_dynamic_binary.f0"><sup class="footnote">[4]</sup></a> 48 </li> 49<li class="listitem"> 50 The library contains a type conversion registry. Because one registry 51 is shared among all extension modules, instances of a class exposed 52 to Python in one dynamically-loaded extension module can be passed 53 to functions exposed in another such module. 54 </li> 55</ul></div> 56</div> 57<div class="section"> 58<div class="titlepage"><div><div><h4 class="title"> 59<a name="building.choosing_a_boost_python_library_.the_static_binary"></a><a class="link" href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_static_binary" title="The Static Binary">The 60 Static Binary</a> 61</h4></div></div></div> 62<p> 63 It might be appropriate to use the static Boost.Python library in any of 64 the following cases: 65 </p> 66<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 67<li class="listitem"> 68 You are <a href="https://docs.python.org/2/extending/extending.html" target="_top">extending</a> 69 python and the types exposed in your dynamically-loaded extension module 70 don't need to be used by any other Boost.Python extension modules, 71 and you don't care if the core library code is duplicated among them. 72 </li> 73<li class="listitem"> 74 You are <a href="https://docs.python.org/2/extending/embedding.html" target="_top">embedding</a> 75 python in your application and either: 76 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "> 77<li class="listitem"> 78 You are targeting a Unix variant OS other than MacOS or AIX, 79 where the dynamically-loaded extension modules can “see” 80 the Boost.Python library symbols that are part of the executable. 81 </li> 82<li class="listitem"> 83 Or, you have statically linked some Boost.Python extension modules 84 into your application and you don't care if any dynamically-loaded 85 Boost.Python extension modules are able to use the types exposed 86 by your statically-linked extension modules (and vice-versa). 87 </li> 88</ul></div> 89 </li> 90</ul></div> 91</div> 92<div class="footnotes"> 93<br><hr style="width:100; text-align:left;margin-left: 0"> 94<div id="ftn.building.choosing_a_boost_python_library_.f0" class="footnote"><p><a href="#building.choosing_a_boost_python_library_.f0" class="para"><sup class="para">[3] </sup></a> 95 Information about how to identify the static and dynamic builds of Boost.Python 96 on <a href="http://boost.org/more/getting_started/windows.html#library-naming" target="_top">Windows</a> 97 / <a href="http://boost.org/more/getting_started/unix-variants.html#library-naming" target="_top">Unix 98 variants</a> 99 </p></div> 100<div id="ftn.building.choosing_a_boost_python_library_.the_dynamic_binary.f0" class="footnote"><p><a href="#building.choosing_a_boost_python_library_.the_dynamic_binary.f0" class="para"><sup class="para">[4] </sup></a> 101 Because of the way most *nix platforms share symbols among dynamically-loaded 102 objects, I'm not certain that extension modules built with different 103 compiler toolsets will always use different copies of the Boost.Python 104 library when loaded into the same Python instance. Not using different 105 libraries could be a good thing if the compilers have compatible 106 ABIs, because extension modules built with the two libraries would 107 be interoperable. Otherwise, it could spell disaster, since an extension 108 module and the Boost.Python library would have different ideas of 109 such things as class layout. I would appreciate someone doing the 110 experiment to find out what happens. 111 </p></div> 112</div> 113</div> 114<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 115<td align="left"></td> 116<td align="right"><div class="copyright-footer">Copyright © 2002-2015 David 117 Abrahams, Stefan Seefeld<br>Copyright © 2002-2015 David Abrahams, Stefan Seefeld<p> 118 Distributed under the Boost Software License, Version 1.0. (See accompanying 119 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>) 120 </p> 121</div></td> 122</tr></table> 123<hr> 124<div class="spirit-nav"> 125<a accesskey="p" href="configuring_boost_build.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../building.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="include_issues.html"><img src="../images/next.png" alt="Next"></a> 126</div> 127</body> 128</html> 129
