1417 lines
52 KiB
HTML
1417 lines
52 KiB
HTML
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<title>Boost Build System</title>
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<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align=
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<h1>Boost Build System</h1>
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<h2><a name="synopsis">Synopsis</a></h2>
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<p>Boost.Build is a system for large project software construction built
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on <a href="jam_src/index.html">Boost.Jam</a>, a descendant of "<a href=
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"http://www.perforce.com/jam/jam.html">Perforce Jam</a>", an open-source
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make replacement<a href="#1">[1]</a>. Key features are:</p>
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<ul>
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<li>A simple target description language</li>
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<li>Build with your choice (or multiple) toolsets from a single command
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invocation</li>
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<li>Build your choice of basic variants (e.g. debug, release,
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profile...) and subvariant modifications (e.g. inlining off) from a
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single command invocation</li>
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<li>``Feature Normalization'' allows target configurations to be
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described independently from the toolset used</li>
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<li>Modular toolset description files allow build instructions for
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different toolsets to be described independently</li>
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<li>Multiple subproject support</li>
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<li>Automatic building of subproject dependencies</li>
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</ul>
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<h2><a name="status">Status</a></h2>
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Boost.Build v1 is a useful, mature system. However, its design and
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structure are not easily adapted to support some of the features we'd
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like to see in the future. To this end, the Boost.Build developers have
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begun work on v2 of Boost.Build, which will be based around this <a href=
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"architecture.html">design document</a>. If you are interested in
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contributing to this effort or you wish to discuss the design of
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Boost.Build, please post inquiries to the <a href=
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"http://groups.yahoo.com/group/jamboost/">jamboost</a> mailing list at
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yahoogroups.
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<p><a href="#design_criteria">Here</a> are some of the design criteria
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that led to these features.</p>
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<h2>Table of Contents</h2>
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<ul>
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<li><a href="#synopsis">Synopsis</a></li>
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<li><a href="#status">Status</a></li>
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<li>
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<a href="#getting_started">Getting Started</a>
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<ul>
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<li><a href="#installing_jam">Installing Boost.Jam</a></li>
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<li><a href="#initiating">Initiating a Build</a></li>
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<li><a href="#setting_variables">Setting Jam Variables</a></li>
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<li><a href="#example_jamfile">An Example Jamfile</a></li>
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<li><a href="#support_files">Support Files</a></li>
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</ul>
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</li>
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<li>
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<a href="#design">Basic Design and Terminology</a>
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<ul>
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<li><a href="#project_subproject">Projects and Subprojects</a></li>
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<li><a href="#targets">Targets</a></li>
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<li><a href="#features">Features and Properties</a></li>
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<li><a href="#variants">Build Variants</a></li>
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<li><a href="#subvariants">Subvariants</a></li>
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<li><a href="#dependents">Dependent Targets</a></li>
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</ul>
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</li>
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<li>
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<a href="#usage">Usage</a>
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<ul>
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<li>
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<a href="#command_line">The Command-Line</a>
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<ul>
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<li><a href="#user_targets">User Targets</a></li>
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<li><a href="#user_globals">Global Variables</a></li>
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</ul>
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</li>
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<li>
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<a href="#subproject_jamfiles">Subproject Jamfiles</a>
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<ul>
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<li><a href="#subproject_rule">The <tt>subproject</tt>
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Rule</a></li>
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<li><a href="#main_targets">Describing Main Targets</a></li>
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<li><a href="#template_targets">Describing Template
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Targets</a></li>
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<li><a href="#stage_targets">Describing Stage Targets</a></li>
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<li><a href="#jamfile_example">Example</a></li>
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</ul>
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</li>
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<li><a href="#feature_description">Feature Descriptions</a></li>
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<li><a href="#variant_description">Variant Descriptions</a></li>
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<li>
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<a href="#toolset_description">Toolset Description Files</a>
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<ul>
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<li><a href="#toolset_example">Example</a></li>
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</ul>
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</li>
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</ul>
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</li>
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<li>
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<a href="#internals">Internals</a>
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<ul>
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<li><a href="#target_names">Target Names</a></li>
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<li><a href="#internal_globals">Global Variables</a></li>
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</ul>
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</li>
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<li>
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<a href="#design_criteria">Design Criteria</a>
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<ul>
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<li><a href="#assumptions">Assumptions</a></li>
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<li><a href="#requirements">Requirements</a></li>
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</ul>
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</li>
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<li><a href="#footnotes">Footnotes</a></li>
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</ul>
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<h2><a name="getting_started">Getting Started</a></h2>
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<h3><a name="installing_jam">Installing Boost.Jam</a></h3>
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Follow these <a href="index.html#Jam">instructions</a> to acquire a bjam
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executable for your platform. Install it somewhere in your path.
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<h3><a name="initiating">Initiating a Build</a></h3>
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<p>Boost.Build responds to several global variable settings. The easiest
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way to get going is usually to use environment variables, though you can
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also set them on the command-line, using
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<tt>-s</tt><i>VARIABLE_NAME</i><tt>=</tt><i>value</i>. In addition to the
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<a href="index.html#Configuring">toolset configuration variables</a>, you
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can use the <tt>TOOLS</tt> variable to indicate which toolset(s) to build
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with, and the <tt>BUILD</tt> variable to describe how you want things
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built. In many cases it should be sufficient to invoke <code>bjam</code>
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with no variable settings.</p>
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<p>Some example Boost.Jam invocations:</p>
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<table border="1" summary="Sample Jam Invocations=">
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<tr>
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<th>Command Line(s)</th>
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<th>Effects</th>
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</tr>
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<tr>
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<td>
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<pre>
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bjam -sTOOLS=gcc my_target
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</pre>
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</td>
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<td>default (debug) <tt><a href="#build">BUILD</a></tt> of
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<tt>my_target</tt>with GCC</td>
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</tr>
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<tr>
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<td>
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<pre>
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bjam -sTOOLS="msvc gcc"
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</pre>
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</td>
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<td>default-build <tt>all</tt> with msvc and gcc</td>
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</tr>
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<tr>
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<td>
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<pre>
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set TOOLS=msvc
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bjam
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</pre>
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</td>
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<td>Set an NT environment variable to always build with MSVC<br>
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default-build <tt>all</tt>.</td>
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</tr>
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<tr>
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<td>
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<pre>
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bjam "-sBUILD=release <debug-symbols>on"
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</pre>
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</td>
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<td>release build with debug symbols of <tt>all</tt> using default
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<tt><a href="#tools">TOOLS</a></tt></td>
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</tr>
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<tr>
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<td>
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<pre>
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bjam -sBUILD="debug release"
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</pre>
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</td>
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<td>debug and release build <tt>all</tt>.</td>
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</tr>
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<tr>
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<td><code>set TOOLS=msvc<br>
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bjam -sBUILD="<cxxflags>/G6"<br>
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</code></td>
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<td>Set an NT environment variable to always build with MSVC<br>
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default-build <tt>all</tt>, adding a compiler command line
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switch</td>
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</tr>
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<tr>
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<td><code>set TOOLS=msvc gcc<br>
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bjam -sBUILD="<msvc><*><cxxflags>/G6"<br>
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</code></td>
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<td>Set an NT environment variable to always build with MSVC and
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GCC<br>
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default-build <tt>all</tt>, adding a MSVC-specific compiler command
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line switch</td>
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</tr>
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<tr>
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<td><code>bjam "-sBUILD=<define>BOOST_POSIX"</code></td>
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<td>build all, with the macro BOOST_POSIX defined for all compilers</td>
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</tr>
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</table>
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<h3><a name="setting_variables">Setting Jam Variables</a></h3>
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<p>The "<tt>-s</tt>" options in the command lines above are passing
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variable settings to the build system. There are actually three ways to
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do that:</p>
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<ul>
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<li>
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Jam picks up variable settings from your environment by default, so
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you can set them there:
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<blockquote>
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<pre>
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> <a href="#build">BUILD</a>="debug release" <i># assuming Unix</i>
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> export <a href="#build">BUILD</a>
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> bjam ...
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</pre>
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</blockquote>
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This approach can be OK for quick-and-dirty tests, but environment
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variable settings tend to be unstable and non-uniform across users
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and machines, so it's best not to rely on the environment much.
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</li>
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<li>Explicitly on the command-line, with the "<tt>-s</tt>" option.</li>
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<li>Directly in Jam code. A project's <a href="#jamrules">Jamrules</a>
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file is a convenient place to make global settings.</li>
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</ul>
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<h3><a name="example_jamfile">An Example Jamfile</a></h3>
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Here is an example of a simple subproject Jamfile. In this example, it is
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assumed that the user has set <tt>BOOST_ROOT</tt>, either as an
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environment variable, on the command-line or in the project's <tt><a
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href="#jamrules">Jamrules</a></tt> file:
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<blockquote>
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<pre>
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subproject foo/bar/baz ; # path to here from project root
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# A static library called 'baz'
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lib baz : baz1.cpp baz2.cpp # C++ sources
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parser/src/baz4.ll # Lex->C++ sources
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parser/src/baz5.yy # Yacc->C++ sources
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: <include>$(BOOST_PARENT_DIRECTORY) # Put boost in #include path
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;
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# An executable called 'test'
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exe test : <lib>baz # use the 'baz' library
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baz_test.cpp # C++ source
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: <include>$(BOOST_ROOT)
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;
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</pre>
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</blockquote>
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<p>That's it! The build system takes care of the rest. If the you want to
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be able to build all subprojects from the project root directory, you can
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add a Jamfile at the root:</p>
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<blockquote>
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<pre>
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project-root ; # declare this to be the project root directory
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# Read subproject Jamfiles
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subinclude foo/bar/baz <font color="#7F7F7F">foo/bar/...</font> ;
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<font color="#7F7F7F">subinclude a/b/c ...</font> ; # more subincludes
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</pre>
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</blockquote>
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<h3><a name="support_files">Support Files</a></h3>
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<p>To use the build system, the following must be located in your
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project's root directory, or in a directory specified in the
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<tt>BOOST_BUILD_PATH</tt> variable. It is usually convenient to specify
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the <tt>BOOST_BUILD_PATH</tt> in your project's <a href=
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"#jamrules">Jamrules</a> file. The <a href="../../Jamrules">Boost
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Jamrules</a> file shows an example.</p>
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<table border="1" summary="Support Files">
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<tr>
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<th>Filename(s)</th>
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<th>Meaning</th>
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</tr>
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<tr>
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<td><i>toolset</i><tt>-tools.jam</tt></td>
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<td>Feature-to-command-line mapping for <i>toolset</i>.</td>
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</tr>
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<tr>
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<td><tt>features.jam</tt></td>
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<td>Abstract toolset feature descriptions.</td>
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</tr>
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<tr>
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<td><tt>boost-base.jam</tt></td>
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<td>Boost build system-specific rule definitions.</td>
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</tr>
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<tr>
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<td><tt>unit-tests.jam</tt></td>
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<td>Unit tests and assertions for boost Jam code.</td>
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</tr>
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</table>
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The <tt>boost-base.jam</tt> file is temporary, and will eventually be
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compiled into our Jam executable.
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<h2><a name="design">Basic Design and Terminology</a></h2>
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This section gives an overview of the way that the system works,
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outlining the system's capabilities and overall design. It also
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introduces the terminology and concepts necessary to understand the
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sections on writing Jamfiles and command-line invocations.
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<h3><a name="project_subproject">Projects and Subprojects</a></h3>
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<p>A <b>project</b> is a source directory tree containing at least one
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<tt>Jamfile</tt>. The root directory of the project is known as the
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<b>project root</b>. <a name="jamrules">The</a> root directory of a
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project may contain a <tt>Jamrules</tt> file, which contains
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project-specific Jam code. If the <tt>Jamrules</tt> file is not present
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when Jam is invoked, a warning will be issued.</p>
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<p>Subdirectories containing <tt>Jamfile</tt>s are called <b>subproject
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directories</b>. Each such <tt>Jamfile</tt> describes a
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<b>subproject</b>.</p>
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<p>The <b>build system installation directory</b> is a directory
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containing Jam files describing compilers and build variants. The
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installation directory can be specified implicitly by setting the
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variable <tt>BOOST_BUILD_PATH</tt>. This lists a set of directories to
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search for the files comprising the build system. If the installation
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directory is not specified, it is the same as the project root, and
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<tt>BOOST_BUILD_PATH</tt> is set to include that directory.</p>
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<h3><a name="targets">Targets</a></h3>
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<p>Each <tt>Jamfile</tt> describes one or more <b>main targets</b>.</p>
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<p>Each main target is an abstract description of one or more <b>built
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targets</b> which are expressions of the corresponding main target under
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particular compilers and build variants. Intermediate files such as
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<tt>.o</tt>/<tt>.obj</tt> files generated by compiling <tt>.cpp</tt>
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files as a consequence of building a main target are also referred to as
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built targets. The term <b>build directory tree</b> refers to the
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location of built target files.</p>
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<ul>
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<li>By default, the build directory tree is overlaid with the project
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directory tree, with targets generated into a subtree rooted at the
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<tt>bin</tt> subdirectory of each subproject directory (the name of
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this directory can be customized by changing the <tt>BIN_DIRECTORY</tt>
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variable.</li>
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<li><a name="all_locate_target">If the variable
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<tt>ALL_LOCATE_TARGET</tt> is set</a>, it specifies an alternate build
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directory tree whose structure mirrors that of the project. In this
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case, built targets of a subproject are generated into the
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corresponding directory of the build directory tree.</li>
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</ul>
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For each main target, there is a corresponding location in the build
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directory tree known as the target's <b>build root</b>, where all
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intermediate and final targets resulting from that main target are
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located.
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<h3><a name="features">Features and Properties</a></h3>
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<p>A <b>feature</b> is a normalized (toolset-independent) description of
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an individual build parameter, such as whether inlining is enabled. Each
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feature usually corresponds to a command-line option of one or more build
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tools. Features come in four varieties:</p>
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<ol>
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<li><b>Simple features</b> can take on any of several predetermined
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values. For example, the feature <tt>optimization</tt> might take one
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of the values <tt>off</tt>, <tt>speed</tt>, or <tt>space</tt>. Simple
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features have a default value. The key aspect of simple features is
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that they are assumed to affect link compatibility: object files
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generated with different values for a simple feature are generated into
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a separate directories, and (with a few exceptions) main targets
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generated with different values won't be linked together.</li>
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<li><b>Free features</b> can either be single-valued, as above, or may
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take on any number of user-specified values simultaneously. For
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example, the <tt>define</tt> feature for a release build might have the
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values <tt>NDEBUG</tt> and <tt>BOOST_RELEASE_BUILD</tt>. Free features
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are assumed not to affect link compatibility.</li>
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<li><b>Path features</b> are free features whose values describe paths
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which may be relative to the subproject (such as linked libraries or
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<tt>#include</tt> search directories). The build system treats the
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values of these features specially to ensure that they are interpreted
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relative to the subproject directory regardless of the directory where
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Jam was invoked.</li>
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<li><b>Dependency features</b> are path features whose values describe
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a dependency of built targets. For example, an external library might
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be specified with a dependency-feature: if the library is updated, the
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target will be updated also. The <tt><library-file></tt> feature
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works this way <a href="#2">[2]</a>.</li>
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</ol>
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<p>A feature-value pair is known as a <b>build property</b>, or simply
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<b>property</b>. The prefixes <i>simple</i>, <i>free</i>, <i>path</i>,
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and <i>dependency</i> apply to properties in an analogous way to
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features.</p>
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<h3><a name="variants">Build Variants</a></h3>
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<p>A build variant, or simply <b>variant</b> is a named set of build
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properties describing how targets should be built. Typically you'll want
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at least two separate variants: one for debugging, and one for your
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release code.</p>
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<p>Built targets for distinct build variants and toolsets are generated
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in separate parts of the build directory tree, known as the <b>variant
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directories</b>. For example, a (sub)project with main targets
|
|
<tt>foo</tt> and <tt>bar</tt>, compiled with both GCC and KAI for
|
|
<tt>debug</tt> and <tt>release</tt> variants might generate the following
|
|
structure (target directories in <b>bold</b>).</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
bin
|
|
+-foo <font color="#7F7F7F"><--- foo's build root</font>
|
|
| +-gcc
|
|
| | +-<b>debug</b>
|
|
| | `-<b>release</b>
|
|
| `-kai
|
|
| +-<b>debug</b>
|
|
| `-<b>release</b>
|
|
`-bar <font color="#7F7F7F"><--- bar's build root</font>
|
|
+-gcc
|
|
| +-<b>debug</b>
|
|
| `-<b>release</b>
|
|
`-kai
|
|
+-<b>debug</b>
|
|
`-<b>release</b>
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<p>The properties constituting a variant may differ according to toolset,
|
|
so <tt>debug</tt> may mean a slightly different set of properties for two
|
|
different compilers.</p>
|
|
|
|
<h3><a name="subvariants">Subvariants</a></h3>
|
|
|
|
<p>When a target is built with <i>simple</i> properties that don't
|
|
exactly match those specified in a build variant, the non-matching
|
|
features are called <b>subvariant features</b> and the target is located
|
|
in a <b>subvariant directory</b> beneath the directory of the base
|
|
variant. This can occur for two reasons:</p>
|
|
|
|
<ol>
|
|
<li>
|
|
Some features are only relevant to certain compilers. When relevant
|
|
simple features have no value specified in the build variant, a value
|
|
must be chosen. Even when the default value is used, the target is
|
|
generated into a subvariant directory. For example, the
|
|
<tt>runtime-link</tt> feature may be unspecified in the
|
|
<tt>debug</tt> variant, but relevant to MSVC. In that case, a
|
|
fragment of the target tree might look like:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
bin
|
|
+-foo <font color="#7F7F7F"><--- foo's build root</font>
|
|
| +-msvc
|
|
| | +-debug
|
|
. . . `-<b>runtime-link-dynamic</b>
|
|
. . .
|
|
</pre>
|
|
</blockquote>
|
|
Because the default value of <tt>runtime-link</tt> is
|
|
<tt>dynamic</tt>, when the <tt>debug</tt> variant is requested, the
|
|
<tt>runtime-link-dynamic</tt> subvariant of foo is built.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>
|
|
It is possible to request (either on the command-line, or as part of
|
|
a main target description) that particular subvariants be built. For
|
|
example, it may be desirable to generate builds that link to the
|
|
runtime both statically <i>and</i> dynamically. In that case, both
|
|
subvariant directories in the example above would be generated:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
bin
|
|
+-foo <font color="#7F7F7F"><--- foo's build root</font>
|
|
| +-msvc
|
|
| | +-debug
|
|
. . . +-<b>runtime-link-dynamic</b>
|
|
. . . `-<b>runtime-link-static</b>
|
|
. . .
|
|
</pre>
|
|
</blockquote>
|
|
</li>
|
|
</ol>
|
|
In no case will targets be built directly into
|
|
<tt>bin/foo/msvc/debug</tt>, since the <tt>debug</tt> variant doesn't
|
|
include the <tt>runtime-link</tt> feature, which is relevant to MSVC.
|
|
|
|
<p>When a subvariant includes multiple subvariant features, targets are
|
|
built into a subvariant directory whose path is determined by
|
|
concatenating the properties sorted in order of their feature names. For
|
|
example, the borland compiler, which uses different libraries depending
|
|
on whether the target is a console or GUI program, might create the
|
|
following structure for a DLL:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
bin
|
|
+-foo <font color="#7F7F7F"><--- foo's build root</font>
|
|
| +-msvc
|
|
| | +-debug
|
|
| | | +-runtime-link-dynamic
|
|
| | | | +-<b>user-interface-console</b>
|
|
| | | | `-<b>user-interface-gui</b>
|
|
. . . `-runtime-link-static
|
|
. . . +-<b>user-interface-console</b>
|
|
. . . `user-interface-gui
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<p>Any configuration of properties for which a target is built, whether
|
|
base variant or subvariant, is known as a <b>build configuration</b>, or
|
|
simply a <b>build</b>.</p>
|
|
|
|
<h3><a name="dependents">Dependent Targets</a></h3>
|
|
|
|
<p>When a main target depends on the product of a second main target (as
|
|
when an executable depends on and links to a static library), each build
|
|
configuration of the dependent target is depends on the
|
|
<i>corresponding</i> build of the dependency. Because only simple
|
|
features participate in build identity, the dependent and dependency
|
|
targets may have completely different free features. This puts the onus
|
|
on the user for ensuring link-compatibility when certain free properties
|
|
are used. For example, when <tt>assert()</tt> is used in header files,
|
|
the preprocessor symbol <tt>NDEBUG</tt> can impact link-compatibility of
|
|
separate compilation units. This danger can be minimized by encapsulating
|
|
such feature differences inside of build variants.</p>
|
|
|
|
<h2><a name="usage">Usage</a></h2>
|
|
|
|
<p>This section describes how to start a build from the command-line and
|
|
how to write project and subproject Jamfiles. It also describes the other
|
|
files written in the Jam language: build-tool specification files,
|
|
feature descriptions files.</p>
|
|
|
|
<h3><a name="command_line">The Command Line</a></h3>
|
|
|
|
<p>This section describes in detail how the build system can be
|
|
invoked.</p>
|
|
|
|
<h4><a name="user_targets">User Targets</a></h4>
|
|
|
|
<p>The Jam command line ends with an optional list of target names; if no
|
|
target names are supplied, the built-in pseudotarget <tt>all</tt> is
|
|
built. In a large project, naming targets can be dicey because of
|
|
collisions. Jam uses a mechanism called <a href="#grist">grist</a> to
|
|
distinguish targets that would otherwise have the same name. Fortunately,
|
|
you won't often have to supply grist at the command-line. When you
|
|
declare a main target, a Jam pseudotarget of the same name is created
|
|
which depends on <i>all</i> of the subvariants requested for your
|
|
invocation of the build system. For example, if your subproject
|
|
declares:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
exe my_target : my_source1.cpp my_source2.c ;
|
|
</pre>
|
|
</blockquote>
|
|
and you invoke Jam with <tt>-sBUILD="debug release" my_target</tt>,
|
|
you will build both the debug and release versions of <tt>my_target</tt>.
|
|
|
|
|
|
<p>These simple, ungristed names are called <b>user targets</b>, and are
|
|
only available for the subproject where Jam is invoked. That way, builds
|
|
from the top level (which may include many Jamfiles through the
|
|
subinclude rule) and builds of library dependencies (which may live in
|
|
other subprojects), don't collide. If it is necessary to refer more
|
|
explicitly to a particular target from the command-line, you will have to
|
|
add ``grist''. Please see <a href="#target_names">this section</a> for a
|
|
more complete description of how to name particular targets in a
|
|
build.</p>
|
|
|
|
<h4><a name="user_globals">Global Variables</a></h4>
|
|
|
|
<p>This is a partial list of global variables that can be set on the
|
|
command-line. Of course you are free to write your own Jam rules which
|
|
interpret other variables from the command-line. This list just details
|
|
some of the variables used by the build system itself. Note also that if
|
|
you don't like the default values you can override them in your project's
|
|
<tt><a href="#jamrules">Jamrules</a></tt> file.</p>
|
|
|
|
<table border="1" summary="User Globals">
|
|
<tr>
|
|
<th>Variable <!-- <th>Meaning --></th>
|
|
|
|
<th>Default</th>
|
|
|
|
<th>Example</th>
|
|
|
|
<th>Notes</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td rowspan="2"><tt><a name="tools">TOOLS</a></tt>
|
|
<!-- <td rowspan="2">Toolsets to build with --></td>
|
|
|
|
<td rowspan="2">Platform-dependent</td>
|
|
|
|
<td><tt>"-sTOOLS=gcc msvc"</tt></td>
|
|
|
|
<td>build with gcc and msvc</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td><tt>-sTOOLS=gcc</tt></td>
|
|
|
|
<td>build with gcc</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td rowspan="4"><tt><a name="build">BUILD</a></tt>
|
|
<!-- <td rowspan="4">Build configuration (see -->
|
|
<!-- <a href="#default_build">here</a>). -->
|
|
</td>
|
|
|
|
<td rowspan="4"><tt>debug</tt></td>
|
|
|
|
<td><tt>-sBUILD=release</tt></td>
|
|
|
|
<td>build the <tt>release</tt> variant</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td><tt>"-sBUILD=debug release"</tt></td>
|
|
|
|
<td>build both <tt>debug</tt> and <tt>release</tt> variants</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td><tt>"-sBUILD=<optimization>speed"</tt></td>
|
|
|
|
<td>build a subvariant of the default variant (<tt>debug</tt>) with
|
|
optimization for speed.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td><tt>"-sBUILD=debug release
|
|
<runtime-link>static/dynamic"</tt></td>
|
|
|
|
<td>build subvariants of the debug and release variants that link to
|
|
the runtime both statically and dynamically.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td><tt>ALL_LOCATE_TARGET</tt>
|
|
<!-- <td>Alternate location for built targets (see <a -->
|
|
<!-- href="#all_locate_target">here</a>) -->
|
|
</td>
|
|
|
|
<td><i>empty</i></td>
|
|
|
|
<td><tt>-sALL_LOCATE_TARGET=~/build</tt></td>
|
|
|
|
<td>Generate all build results in the <tt>build</tt> subdirectory of
|
|
the user's home directory (UNIX).</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<h3><a name="#subproject_jamfiles">SubProject Jamfiles</a></h3>
|
|
This section describes how to write a Jamfile for a subproject.
|
|
|
|
<h4><a name="subproject_rule">The <tt>subproject</tt> rule</a></h4>
|
|
|
|
<p>A subproject's Jamfile begins with an invocation of the
|
|
<tt>subproject</tt> rule that specifies the subproject's location
|
|
relative to the top of the project tree:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
subproject <i>path-from-top</i> ;
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<p>The <tt>subproject</tt> rule tells the build system where to place
|
|
built targets from the subproject in case <tt>ALL_LOCATE_TARGET</tt> is
|
|
used to specify the build directory tree. If there is a Jamfile in the
|
|
project root directory, you should use the <tt>project-root</tt> rule
|
|
instead:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
project-root ;
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<h4><a name="main_targets">Describing Main Targets</a></h4>
|
|
|
|
<p>A main target is described using the following syntax:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
<i>target-type</i> <i>name</i> : <i>sources</i>
|
|
[ : <i>requirements</i> [ : <i><a href=
|
|
"#default_build">default-BUILD</a></i> ] ] ;
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<ul>
|
|
<li><i>target-type</i> may be one of <tt>exe</tt>, <tt>lib</tt>,
|
|
<tt>dll</tt>, <tt>stage</tt> or <tt>template</tt>. These are actually
|
|
names of Jam rules. Additional main target rules are possible; see
|
|
<tt><a href="../../status/Jamfile">status/Jamfile</a></tt> or <tt><a
|
|
href=
|
|
"../../libs/python/build/Jamfile">libs/python/build/Jamfile</a></tt>
|
|
for examples.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><i>name</i> specifies the name of the main target, multiple targets
|
|
with the same name are allowed but only if they are of different types.
|
|
Normally this is not the name of the final target file generated. The
|
|
target file name depends on the type of target which controls how the
|
|
base target name is renamed to conform to platform conventions. For
|
|
<tt>exe</tt>s the name might be the same or <tt>*.exe</tt>. For
|
|
<tt>lib</tt>s the name might be <tt>*.lib</tt> or <tt>lib*.a</tt>. And
|
|
for <tt>dll</tt>s the name might be <tt>*.dll</tt> or <tt>lib*.so</tt>.
|
|
For platform specific naming consult the <tt><a href=
|
|
"allyourbase.jam">allyourbase.jam</a></tt> file in the build
|
|
system.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><i>sources</i> is a list of paths to source files and dependency
|
|
targets. A dependency target path is preceded by
|
|
<tt><template></tt>, <tt><lib></tt>, <tt><dll></tt>,
|
|
or <tt><exe></tt>, and the final path component specifies the
|
|
name of a main target in a Jamfile located in the directory given by
|
|
the initial path components. Paths may be absolute or relative. The
|
|
type of dependency is also used to decide how to link to it when
|
|
needed. Specifying a <tt><lib></tt> indicates the use of static
|
|
linking, as opposed to specifying a <tt><dll></tt> which uses
|
|
dynamic linking. For example in Unix static linking will be done
|
|
directly, and dynamic linking with the common "<tt>-l</tt>" liker flag
|
|
and use of <tt>LD_LIBRARY_PATH</tt>.<br>
|
|
<br>
|
|
<b>NOTE:</b> It is important to match up the type of source dependency
|
|
with the same type the dependency is built as. Trying to specify a
|
|
source dependency of <tt><lib></tt> when the target is defined as
|
|
a <tt><dll></tt> will cause an error.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>
|
|
<i><a name="target_requirements">requirements</a></i> specifies the
|
|
build properties intrinsic to the target. Requirements are given as
|
|
sets of optionally-<b>qualified build properties</b>:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
[[<<i>compiler</i>>]<<i>variant</i>>]<<i>feature</i>><i>value</i>
|
|
</pre>
|
|
</blockquote>
|
|
<tt><<i>compiler</i>></tt> and <tt><<i>variant</i>></tt>,
|
|
if supplied, can be used to restrict the applicability of the
|
|
requirement. Either one may be replaced by <tt><*></tt>, which
|
|
is the same as omitting it.
|
|
|
|
<p>The system checks that simple feature requirements are not
|
|
violated by explicit subvariant build requests, and will issue a
|
|
warning otherwise. Free features specified as requirements are simply
|
|
added to each corresponding build configuration.<br>
|
|
<br>
|
|
</p>
|
|
</li>
|
|
|
|
<li>
|
|
<i><a name="default_build">default-BUILD</a></i> specifies the
|
|
configurations that should be built if the <tt><a href=
|
|
"#build">BUILD</a></tt> variable is not otherwise specified. Any
|
|
elements not beginning with ``<tt><</tt>...<tt>></tt>'' refer
|
|
to build variants. Other elements use the same syntax as the <a href=
|
|
"#target_requirements">requirements</a> described above, except that
|
|
multiple values may be specified for a simple feature by separating
|
|
them with a slash, forming (qualified) <b>multi-valued
|
|
properties</b>:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
[[<<i>compiler</i>>]<<i>variant</i>>]<<i>feature</i>><i>value1</i>[/<i>value2</i>...]
|
|
</pre>
|
|
</blockquote>
|
|
When multiple values are specified, it causes <i>all</i> the implied
|
|
configurations to be built by default. It is also possible to prevent
|
|
any default builds from occurring on this target by using
|
|
<code><suppress>true</code> . This suppresses any local
|
|
targets, either implicit or explicit, from building. But, this does
|
|
not prevent implied targets as required by a dependency by another
|
|
target to this one from being built. This is useful, for example, for
|
|
defining a set of libraries generically and having them built only
|
|
when another target like an exe is built. Such use might look like:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
lib basic : basic.cpp : : <suppress>true ;<br>
|
|
<br>
|
|
exe test : test.cpp <lib>basic ;<br>
|
|
</pre>
|
|
</blockquote>
|
|
With that the <tt>basic</tt> library will only be built when the
|
|
<tt>test</tt> executable is built, and only the variations required
|
|
by the executable will be built.<br>
|
|
</li>
|
|
</ul>
|
|
|
|
<p><b>NOTE:</b> for simple features in both <i><a href=
|
|
"#target_requirements">requirements</a></i> and <i><a href=
|
|
"#default_build">default-BUILD</a></i>, more-specific qualification
|
|
overrides less-specific.</p>
|
|
|
|
<h4><a name="template_targets">Describing Template Targets</a></h4>
|
|
|
|
<p>Template targets provide a way to handle commonalities between
|
|
projects targets. They have the same form as <a href="#main_targets">main
|
|
targets</a> but do not initiate build requests. A target that lists a
|
|
template as a dependency inherits all the settings from the template,
|
|
i.e. the templates sources, requirements and default build settings will
|
|
be added to the targets settings. Paths mentioned in a template
|
|
definition are always relative to the subdirectory of the Jamfile
|
|
containing the templates definition, regardless of the subdirectory of
|
|
the dependent main target. Typically a project will have at least one
|
|
template target that handles defines, include paths and additional
|
|
compiler flags common to all targets in the project.</p>
|
|
|
|
<h4><a name="stage_targets">Describing Stage Targets</a></h4>
|
|
|
|
<p>Stage targets are a special kind of target that don't build a single
|
|
file but to a collection of files. The goal is to create a directory
|
|
which is composed of the various files that other targets generate, or
|
|
individual files. When built a stage target creates a directory with the
|
|
same name as the target, and copies the dependent files to it. The form
|
|
of the target is the same as that of <a href="#main_targets">main
|
|
targets</a> with some differences...</p>
|
|
|
|
<ul>
|
|
<li><i>target-type</i> is <tt>stage</tt>. See <tt><a href=
|
|
"../../libs/regex/build/Jamfile">libs/regex/build/Jamfile</a></tt> for
|
|
an example.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><i>Name</i> specifies the name of the stage and is the name of the
|
|
directory created.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><i>sources</i> is the same as main targets and one can list both
|
|
generated targets like <tt><exe>test_exe</tt> and individual
|
|
files, but not template targets.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>
|
|
<i>Requirements</i> the build properties specified are used as with
|
|
main targets. But one additional type of requirement is possible:
|
|
<tt><tag></tt>... A tag specifies how to "augment" the names of
|
|
the copied files. This is needed to distinguish the various files if
|
|
your collecting different builds of the same targets. The syntax is:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
<tag><<i>feature|variant</i>><i>value</i>
|
|
</pre>
|
|
</blockquote>
|
|
<br>
|
|
If the <tt><i>feature</i></tt> or <tt><i>variant</i></tt> is present
|
|
for the a target the file for that target is renamed to include the
|
|
given <tt><i>value</i></tt> between the basename and the suffix. Two
|
|
special <tt>tag</tt>s, <tt><tag><prefix></tt> and
|
|
<tt><tag><postfix></tt>, let one prepend and append a
|
|
value to the "augmentation" respectively.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><i>default-BUILD</i> acts in the same manner as a main target.<br>
|
|
</li>
|
|
</ul>
|
|
|
|
<h4><a name="jamfile_example">Example</a></h4>
|
|
|
|
<p>This artificially complex example shows how two executables called
|
|
"foo" and "fop" might be described in a Jamfile. All common settings are
|
|
factored out in the templates "base" and "executable". Foo is composed of
|
|
the sources <tt>./foo.cpp</tt> and <tt>./src/bar.cpp</tt> (specified
|
|
relative to the directory in which the Jamfile resides). Fop only has one
|
|
sourcefile <tt>./fop.cpp</tt>. Both executables link against the built
|
|
target which results from building the target <tt>baz</tt> as described
|
|
in <tt>../bazlib/Jamfile</tt>.</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
template base :
|
|
## <a href="#target_requirements">Requirements</a> ##
|
|
: <include>../bazlib/include
|
|
<define>BUILDING_FOO=1
|
|
<release><define>FOO_RELEASE
|
|
<msvc><*><define>FOO_MSVC
|
|
<msvc><release><define>FOO_MSVC_RELEASE
|
|
<gcc><*><optimization>off
|
|
<gcc><release><optimization>space
|
|
<threading>multi
|
|
<sysinclude>/usr/local/foolib/include
|
|
|
|
## <a href="#default_build">default-BUILD</a> ##
|
|
: debug release
|
|
<debug><runtime-link>static/dynamic
|
|
;
|
|
|
|
template executable : <template>base <lib>../bazlib/baz ;
|
|
|
|
exe foo : <template>executable foo.cpp src/bar.cpp ;
|
|
|
|
exe fop : <template>executable fop.cpp ;
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<p>The <a href="#target_requirements">requirements</a> section:</p>
|
|
|
|
<ul>
|
|
<li>Adds <tt>../bazlib/include</tt> to the <tt>#include</tt> path</li>
|
|
|
|
<li>Sets the preprocessor symbol <tt>BUILDING_FOO</tt> to
|
|
<tt>1</tt></li>
|
|
|
|
<li>In the <tt>release</tt> builds, <tt>#define</tt>s
|
|
<tt>FOO_RELEASE</tt>.</li>
|
|
|
|
<li>When built with MSVC, <tt>#define</tt>s <tt>FOO_MSVC</tt>.</li>
|
|
|
|
<li>In <tt>release</tt> variants built with MSVC, <tt>#define</tt>s
|
|
<tt>FOO_MSVC_RELEASE</tt>.</li>
|
|
|
|
<li>Most builds under GCC have optimization turned off, but...</li>
|
|
|
|
<li>...GCC <tt>release</tt> builds require optimization for space.</li>
|
|
|
|
<li>Requires multithread support on compilers where it's relevant.</li>
|
|
|
|
<li>Adds <tt>/usr/local/foolib/include</tt> to the <tt>#include
|
|
<*></tt> path</li>
|
|
</ul>
|
|
|
|
<p>The <a href="#default_build">default-BUILD</a> section:</p>
|
|
|
|
<ul>
|
|
<li>specifies that <tt>debug</tt> and <tt>release</tt> base variants
|
|
are built by default.</li>
|
|
|
|
<li>on compilers where the feature is relevant, requests both
|
|
statically- and dynamically-linked subvariants of the debug
|
|
variant.</li>
|
|
</ul>
|
|
|
|
<h3><a name="feature_description">Feature Descriptions</a></h3>
|
|
|
|
<p>Features are described by stating the feature type (simple features
|
|
are specified with "<tt>feature</tt>"), followed by the feature name. An
|
|
optional second argument can be used to list the permissible values of
|
|
the feature. Examples can be found in <a href=
|
|
"features.jam">features.jam</a>.</p>
|
|
|
|
<h3><a name="variant_description">Variant Descriptions</a></h3>
|
|
|
|
<p>Variants are described with the following syntax:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
variant <i>name</i> : [<<i>toolset-name</i>>]<<i>feature</i>>value... ;
|
|
</pre>
|
|
</blockquote>
|
|
The <tt>variant</tt> rule specifies the list of properties comprising a
|
|
variant. Properties may be optionally qualified with a toolset name,
|
|
which specifies that the property applies only to that toolset. One or
|
|
more parent variants may be specified to inherit the properties
|
|
from those parent(s). For inherited properties precedence is given
|
|
on a left to right order, making the immediate properties override those
|
|
in the parent(s). This can be used to great effect for describing global
|
|
properties that are shared amongst various variants, and therefore
|
|
targets. For example:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
variant my-globals : <rtti>off ;
|
|
|
|
variant my-debug : my-globals debug ;
|
|
|
|
variant my-release : my-globals release ;
|
|
</pre>
|
|
</blockquote>
|
|
More examples can be found in <a href="features.jam">features.jam</a>.
|
|
|
|
<h3><a name="toolset_description">Toolset Description Files</a></h3>
|
|
|
|
<p>Toolset descriptions are located in the project's root directory, or a
|
|
directory specified by <tt>BOOST_BUILD_INSTALLATION</tt>, which may be
|
|
set in a <tt>Jamfile</tt> or the project's <tt><a href=
|
|
"#jamrules">Jamrules</a></tt> file. Each file is called
|
|
<i>toolset-name</i><tt>-tools.jam</tt>, where <i>toolset-name</i> is the
|
|
name of the toolset. The toolset description file has two main jobs:</p>
|
|
|
|
<ol>
|
|
<li>
|
|
redefine the following rules:
|
|
|
|
<ul>
|
|
<li><tt>Link-action</tt> - links an executable from objects and
|
|
libraries</li>
|
|
|
|
<li><tt>Archive-action</tt> - links a static library from object
|
|
files</li>
|
|
|
|
<li><tt>C++-action</tt> - compiles a 'C++' file into an object
|
|
file</li>
|
|
|
|
<li><tt>Cc-action</tt> - compiles a 'C' file into an object
|
|
file</li>
|
|
</ul>
|
|
These rules should simply invoke the action part of a rule whose name
|
|
is uniquely defined for the toolset. For example,
|
|
|
|
<blockquote>
|
|
<pre>
|
|
rule C++-action
|
|
{
|
|
msvc-C++-action $(<) : $(>) ;
|
|
}
|
|
|
|
actions msvc-C++-action
|
|
{
|
|
cl -nologo -GX -c -U$(UNDEFS) -D$(DEFINES) $(CFLAGS) $(C++FLAGS) -I$(HDRS) -I$(STDHDRS) -Fo$(<) -Tp$(>)
|
|
}
|
|
|
|
</pre>
|
|
</blockquote>
|
|
Note that <tt>Link-action</tt> may require special care: on platforms
|
|
where the global variable <tt>gEXPORT_SUFFIX(DLL)</tt> is defined
|
|
(e.g. Windows), the first argument may have two elements when linking
|
|
a shared library. The first is the shared library target, and the
|
|
second is the import library target, with suffix given by
|
|
<tt>$(gEXPORT_SUFFIX(DLL))</tt>. It will always have a third argument
|
|
which is either ``<tt>EXE</tt>'' or ``<tt>DLL</tt>''. This can be
|
|
used to dispatch to different actions for linking DLLs and EXEs if
|
|
necessary, but usually it will be easier to take advantage of the
|
|
special <tt><target-type></tt> feature, which will have the
|
|
same value using the <tt>flags</tt> rule described below.
|
|
</li>
|
|
|
|
<li>
|
|
Translate build settings given in the global
|
|
<tt>gBUILD_PROPERTIES</tt> variable into something that can be used
|
|
by the toolset. The build system provides the <tt>flags</tt> rule to
|
|
help translate build properties into elements of global variables
|
|
which are later attached to targets so that they can affect the build
|
|
actions. The <tt>flags</tt> rule is used as follows:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
flags <i>toolset variable condition</i> [: <i>value</i>...]
|
|
</pre>
|
|
</blockquote>
|
|
The parameters are:
|
|
|
|
<ul>
|
|
<li><i>toolset</i> - the name of the toolset</li>
|
|
|
|
<li><i>variable</i> - the name of a global variable which can be
|
|
used to carry information to a command-line</li>
|
|
|
|
<li>
|
|
<i>condition</i> - one one or more elements in the following
|
|
forms:
|
|
|
|
<ol>
|
|
<li>a property-set of the form:
|
|
<tt><<i>feature</i>><i>value</i></tt>[<tt>/<<i>feature</i>>
|
|
<i>value</i></tt>...]</li>
|
|
|
|
<li><tt><<i>feature</i>></tt></li>
|
|
</ol>
|
|
</li>
|
|
|
|
<li><i>values</i> - anything</li>
|
|
</ul>
|
|
|
|
<p>Semantics only affect targets built with the specified toolset,
|
|
and depend on the target's build configuration:</p>
|
|
|
|
<ol>
|
|
<li>if any specified property-set is a subset of the target's build
|
|
properties, the <i>values</i> specified in <tt>$(3)</tt> will be
|
|
appended once to <i>variable</i>.</li>
|
|
|
|
<li>The value of each specified feature that participates in the
|
|
target's build properties is appended to <i>variable</i>. In either
|
|
case, the variable will be set "on" the target so it may be used in
|
|
the build actions.</li>
|
|
</ol>
|
|
</li>
|
|
</ol>
|
|
|
|
<h4><a name="toolset_example">Example</a></h4>
|
|
|
|
<p>The description of the <tt>flags</tt> rule above is actually more
|
|
complicated than it sounds. For example, the following line might be used
|
|
to specify how optimization can be turned off for MSVC:</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
flags msvc CFLAGS <optimization>off : /Od ;
|
|
</pre>
|
|
</blockquote>
|
|
It says that the string <tt>/Od</tt> should be added to the global
|
|
<tt>CFLAGS</tt> variable whenever a build configuration includes the
|
|
property <tt><optimization>off</tt>.
|
|
|
|
<p>Similarly, in the following example,</p>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
flags msvc CFLAGS <runtime-build>release/<runtime-link>dynamic : /MD ;
|
|
</pre>
|
|
</blockquote>
|
|
we add <tt>/MD</tt> to the CFLAGS variable when both of the specified
|
|
conditions are satisfied. We could grab all of the values of the free
|
|
feature <tt><include></tt> in the <tt>HDRS</tt> variable as
|
|
follows:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
flags msvc HDRS <include> ;
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<p>The use of these variables should be apparent from the declaration of
|
|
<tt>actions msvc-C++-action</tt> in the previous section.</p>
|
|
|
|
<h2><a name="internals">Internals</a></h2>
|
|
|
|
<h3><a name="target_names">Target Names</a></h3>
|
|
|
|
<p>In addition to <a href="#user_targets">user targets</a>, which
|
|
correspond directly to the names the user writes in her subproject
|
|
Jamfile, several additional targets are generated, regardless of the
|
|
directory from which Jam was invoked:</p>
|
|
|
|
<ul>
|
|
<li>A <b>main target</b> has all the same dependencies as a user target
|
|
(i.e. building it updates all requested subvariants). Its name is the
|
|
same except for the addition of <tt>$(SOURCE_GRIST)</tt>, which
|
|
identifies the subproject. The identification looks like the names of
|
|
the path components from the project root to the subproject, separated
|
|
by exclamation points. Thus, if the project is rooted at <tt>foo</tt>,
|
|
in the subproject at <tt>foo/bar/baz</tt> the target <tt>my_target</tt>
|
|
is identified by <tt><bar!baz>my_target</tt>.</li>
|
|
|
|
<li>A <b>subvariant target</b> has additional grist identifying its
|
|
main target and subvariant. This grist is joined to
|
|
<tt>$(SOURCE_GRIST)</tt> with the platform's directory separator. Thus,
|
|
on UNIX, a subvariant target of <tt>my_target</tt> above might be
|
|
identified as
|
|
<tt><bar!baz/my_target/optimization-space/runtime-link-static>my_source.o</tt>.
|
|
Note that the part of the grist following the first slash, known as the
|
|
<b>subvariant id</b>, also corresponds to a fragment of the subvariant
|
|
directory path where the corresponding target is generated. Most built
|
|
targets will be identified this way.</li>
|
|
</ul>
|
|
|
|
<h3><a name="internal_globals">Global Variables</a></h3>
|
|
|
|
<p>This section describes some of the global variables used by the build
|
|
system. Please note that some parts of the system (particularly those in
|
|
<tt>allyourbase.jam</tt>) are heavily based on the Jambase file supplied
|
|
with Jam, and as such do not follow the conventions described below.</p>
|
|
|
|
<p>Global variables used in the build system fall into three
|
|
categories:</p>
|
|
|
|
<ul>
|
|
<li>Global variables intended to be set by the user on the command-line
|
|
or in the environment use <tt>ALL_UPPER_CASE</tt> names.</li>
|
|
|
|
<li>Internal global variables begin with a lower-case "g" and continue
|
|
in upper-case: <tt>gSOME_GLOBAL</tt></li>
|
|
|
|
<li>
|
|
Global variables of the form:
|
|
<tt>gBASE_NAME(</tt><i>arguments</i><tt>)</tt>, where
|
|
<i>arguments</i> is a comma-separated argument list, are used
|
|
internally to achieve a kind of indirection by concatenating variable
|
|
values:
|
|
|
|
<blockquote>
|
|
<pre>
|
|
ECHO $(gFUBAR($(x),$(y))) ;
|
|
</pre>
|
|
</blockquote>
|
|
</li>
|
|
</ul>
|
|
|
|
<p>Please note that the build system commonly takes advantage of <a href=
|
|
"jam_src/Jam.html#bindingmods">Jam's
|
|
Dynamic Scoping feature</a> (see the <tt>local</tt> command in the "Flow
|
|
of Control" section below the link target) to temporarily "change" a
|
|
global variable by declaring a <tt>local</tt> of the same name.</p>
|
|
|
|
<p>Many of the variables that are used to configure how Boost.Build works
|
|
internally are listed <a href="variables.html">here</a> with brief
|
|
descriptions.</p>
|
|
|
|
<h3>Variables Associated with SubProject Identity</h3>
|
|
|
|
<ul>
|
|
<li><tt>SUBDIR_TOKENS</tt> - a list of the path elements relative to
|
|
the project root of the current subproject.</li>
|
|
|
|
<li><tt>SUBDIR</tt> - the path from the invocation directory to the
|
|
current subproject directory.</li>
|
|
</ul>
|
|
|
|
<h3>Grist Variables</h3>
|
|
|
|
<ul>
|
|
<li><tt>TARGET_GRIST</tt> takes the form
|
|
<tt><i>subproject!id</i>/target/toolset/variant/<i>subvariant-path</i></tt>.</li>
|
|
</ul>
|
|
|
|
<h2><a name="design_criteria">Design Criteria</a></h2>
|
|
|
|
<h3><a name="assumptions">Assumptions</a></h3>
|
|
|
|
<p>The requirements are driven by several basic assumptions:</p>
|
|
|
|
<ul>
|
|
<li>There is no single Boost developer or test facility with access to
|
|
or knowledge of all the platforms and compilers Boost libraries are
|
|
used with.</li>
|
|
|
|
<li>Boost libraries are used across such a wide range of platforms and
|
|
compilers that almost no other assumptions can be made.</li>
|
|
</ul>
|
|
|
|
<h3><a name="requirements">Requirements</a></h3>
|
|
|
|
<p>This build system was designed to satisfy the following
|
|
requirements:</p>
|
|
|
|
<ul>
|
|
<li>A developer adding a new library or test program must only have to
|
|
add simple entries naming the source files to a text file, and not have
|
|
to know anything about platform specific files. The developer should
|
|
not have to supply header dependency information.</li>
|
|
|
|
<li>There should be a very high likelihood of builds succeeding on all
|
|
platforms if a build succeeds on any platform. In other words, a
|
|
developer must not be required to have access to many platforms or
|
|
compilers to ensure correct builds</li>
|
|
|
|
<li>A user or developer adding support for a new platform or compiler
|
|
should only have to add to a single file describing how to do the build
|
|
for that platform or compiler, and shouldn't have to identify the files
|
|
that will need to be built.</li>
|
|
|
|
<li>The build should rely only on tools native to the platform and
|
|
compiler, or supplied via the boost download.</li>
|
|
|
|
<li>The details of how the build is done for a particular platform or
|
|
compiler should be appropriate for that platform.</li>
|
|
|
|
<li>It should be possible to build multiple variants (e.g.
|
|
debug/release) of a single target.</li>
|
|
|
|
<li>It should be possible to build multiple variants of multiple
|
|
targets with multiple compilers from a single build command.</li>
|
|
|
|
<li>The build tools must be able to handle Boost growth issues such as
|
|
identified in Directory Structure proposals and discussion.</li>
|
|
|
|
<li>Support for dynamic and static linking should be included.</li>
|
|
|
|
<li>It should be relatively straightforward to add support for a new
|
|
compiler. In most cases, no modification of files used to describe
|
|
existing targets should be required.</li>
|
|
|
|
<li>Support for compiler- and variant-specific configuration for each
|
|
target</li>
|
|
|
|
<li>It should be possible to build targets into a directory unrelated
|
|
to the source directories (they may be read-only)</li>
|
|
</ul>
|
|
|
|
<h2><a name="footnotes">Footnotes</a></h2>
|
|
<a name="1">[1]</a> Boost Jam is actually descended directly from <a
|
|
href="http://freetype.sourceforge.net/jam/index.html">FTJam</a>, which
|
|
was itself a variant of <a href=
|
|
"http://www.perforce.com/jam/jam.html">Jam/MR</a>. It is hoped that
|
|
crucial features we rely on will eventually be incorporated back into the
|
|
Jam/MR release.
|
|
|
|
<p><a name="2">[2]</a> Note: right now, a dependency feature of a main
|
|
target makes <b>all</b> resulting built targets dependent, including
|
|
intermediate targets. That means that if an executable is dependent on an
|
|
external library, and that library changes, all the sources comprising
|
|
the executable will be recompiled as well. This behavior should probably
|
|
be fixed.</p>
|
|
<hr>
|
|
|
|
<p>© Copyright David Abrahams 2001. Permission to copy, use, modify,
|
|
sell and distribute this document is granted provided this copyright
|
|
notice appears in all copies. This document is provided "as is" without
|
|
express or implied warranty, and with no claim as to its suitability for
|
|
any purpose.</p>
|
|
|
|
<p>Revised
|
|
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan
|
|
-->24 May, 2002
|
|
<!--webbot bot="Timestamp" endspan i-checksum="13972"
|
|
-->
|
|
</p>
|
|
</body>
|
|
</html>
|
|
|