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28 <h2><span class=
"refentrytitle">Macro BOOST_LOCAL_FUNCTION_CONFIG_LOCALS_AS_TPARAMS
</span></h2>
29 <p>BOOST_LOCAL_FUNCTION_CONFIG_LOCALS_AS_TPARAMS
— Specify when local functions can be passed as template parameters without introducing any run-time overhead.
</p>
31 <h2 xmlns:
rev=
"http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class=
"refsynopsisdiv-title">Synopsis
</h2>
32 <div xmlns:
rev=
"http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class=
"refsynopsisdiv"><pre class=
"synopsis"><span class=
"comment">// In header:
<<a class=
"link" href=
"reference.html#header.boost.local_function.config_hpp" title=
"Header <boost/local_function/config.hpp>">boost/local_function/config.hpp
</a>>
34 </span>BOOST_LOCAL_FUNCTION_CONFIG_LOCALS_AS_TPARAMS
</pre></div>
35 <div class=
"refsect1">
36 <a name=
"id907270"></a><h2>Description
</h2>
37 <p>If this macro is defined to
<code class=
"computeroutput">1</code>, this library will assume that the compiler allows to pass local classes as template parameters:
</p>
38 <pre class=
"programlisting"><span class=
"keyword">template
</span><span class=
"special"><</span><span class=
"keyword">typename
</span> <span class=
"identifier">T
</span><span class=
"special">></span> <span class=
"keyword">void
</span> <span class=
"identifier">f
</span><span class=
"special">(
</span><span class=
"keyword">void
</span><span class=
"special">)
</span> <span class=
"special">{
</span><span class=
"special">}
</span>
40 <span class=
"keyword">int
</span> <span class=
"identifier">main
</span><span class=
"special">(
</span><span class=
"keyword">void
</span><span class=
"special">)
</span> <span class=
"special">{
</span>
41 <span class=
"keyword">struct
</span> <span class=
"identifier">local_class
</span> <span class=
"special">{
</span><span class=
"special">}
</span><span class=
"special">;
</span>
42 <span class=
"identifier">f
</span><span class=
"special"><</span><span class=
"identifier">local_class
</span><span class=
"special">></span><span class=
"special">(
</span><span class=
"special">)
</span><span class=
"special">;
</span>
43 <span class=
"keyword">return
</span> <span class=
"number">0</span><span class=
"special">;
</span>
44 <span class=
"special">}
</span>
46 <p> This is the case for C++
11 compilers and some C++
03 compilers (e.g., MSVC), but it is not the case in general for most C++
03 compilers (including GCC). This will allow the library to pass local functions as template parameters without introducing any run-time overhead (specifically without preventing the compiler from optimizing local function calls by inlining their assembly code).
</p>
47 <p>If this macro is defined to
<code class=
"computeroutput">0</code> instead, this library will introduce a run-time overhead associated to resolving a function pointer call in order to still allow to pass the local functions as template parameters.
</p>
48 <p>It is recommended to leave this macro undefined. In this case, the library will automatically define this macro to
<code class=
"computeroutput">0</code> if the Boost.Config macro
<code class=
"computeroutput">BOOST_NO_CXX11_LOCAL_CLASS_TEMPLATE_PARAMETERS
</code> is defined for the specific compiler, and to
<code class=
"computeroutput">1</code> otherwise.
</p>
49 <p><span class=
"bold"><strong>See:
</strong></span> <a class=
"link" href=
"boost_localfunction/getting_started.html" title=
"Getting Started"> Getting Started
</a> section,
<a class=
"link" href=
"boost_localfunction/advanced_topics.html" title=
"Advanced Topics"> Advanced Topics
</a> section,
<code class=
"computeroutput"><a class=
"link" href=
"BOOST_LOCAL_FUNCTION_NAME.html" title=
"Macro BOOST_LOCAL_FUNCTION_NAME">BOOST_LOCAL_FUNCTION_NAME
</a></code>.
</p>
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"copyright-footer">Copyright
© 2009-
2012 Lorenzo
56 Distributed under the Boost Software License, Version
1.0 (see accompanying
57 file LICENSE_1_0.txt or a copy at
<a href=
"http://www.boost.org/LICENSE_1_0.txt" target=
"_top">http://www.boost.org/LICENSE_1_0.txt
</a>)
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