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					<h1>mem_fn.hpp</h1>
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				<td colspan="2" height="64">&nbsp;</td>
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		<h2>Contents</h2>
		<h3 style="MARGIN-LEFT: 20pt"><a href="#Purpose">Purpose</a></h3>
		<h3 style="MARGIN-LEFT: 20pt"><a href="#FAQ">Frequently Asked Questions</a></h3>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Q1">Can <b>mem_fn</b> be used instead of the 
				standard <b>std::mem_fun[_ref]</b> adaptors?</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Q2">Should I replace every occurence of <b>std::mem_fun[_ref]</b>
				with <b>mem_fn</b> in my existing code?</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Q3">Does <b>mem_fn</b> work with COM methods?</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Q4">Why isn't BOOST_MEM_FN_ENABLE_STDCALL 
				defined automatically?</a></h4>
		<h3 style="MARGIN-LEFT: 20pt"><a href="#Interface">Interface</a></h3>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Synopsis">Synopsis</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#CommonRequirements">Common requirements</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#get_pointer">get_pointer</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#mem_fn">mem_fn</a></h4>
		<h3 style="MARGIN-LEFT: 20pt"><a href="#Implementation">Implementation</a></h3>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Files">Files</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#Dependencies">Dependencies</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#NumberOfArguments">Number of Arguments</a></h4>
		<h4 style="MARGIN-LEFT: 40pt"><a href="#stdcall">"__stdcall", "__cdecl" and 
				"__fastcall" Support</a></h4>
		<h3 style="MARGIN-LEFT: 20pt"><a href="#Acknowledgements">Acknowledgements</a></h3>
		<h2><a name="Purpose">Purpose</a></h2>
		<p>
			<b>boost::mem_fn</b> is a generalization of the standard functions <b>std::mem_fun</b>
			and <b>std::mem_fun_ref</b>. It supports member function pointers with more 
			than one argument, and the returned function object can take a pointer, a 
			reference, or a smart pointer to an object instance as its first argument. <STRONG>mem_fn</STRONG>
			also supports pointers to data members by treating them as functions taking no 
			arguments and returning a (const) reference to the member.
		</p>
		<p>
			The purpose of <b>mem_fn</b> is twofold. First, it allows users to invoke a 
			member function on a container with the familiar
		</p>
		<pre>
    std::for_each(v.begin(), v.end(), boost::mem_fn(&amp;Shape::draw));
</pre>
		<p>
			syntax, even when the container stores smart pointers.
		</p>
		<p>
			Second, it can be used as a building block by library developers that want to 
			treat a pointer to member function as a function object. A library might define 
			an enhanced <b>for_each</b> algorithm with an overload of the form:
		</p>
		<pre>
template&lt;class It, class R, class T&gt; void for_each(It first, It last, R (T::*pmf) ())
{
    std::for_each(first, last, boost::mem_fn(pmf));
}
</pre>
		<p>
			that will allow the convenient syntax:
		</p>
		<pre>
    for_each(v.begin(), v.end(), &amp;Shape::draw);
</pre>
		<p>
			When documenting the feature, the library author will simply state:
		</p>
		<h4 style="MARGIN-LEFT: 20pt">template&lt;class It, class R, class T&gt; void 
			for_each(It first, It last, R (T::*pmf) ());</h4>
		<p style="MARGIN-LEFT: 20pt">
			<b>Effects:</b> equivalent to std::for_each(first, last, boost::mem_fn(pmf));
		</p>
		<p>
			where <b>boost::mem_fn</b> can be a link to this page. See <a href="bind.html">the 
				documentation of <b>bind</b></a> for an example.
		</p>
		<p>
			<b>mem_fn</b> takes one argument, a pointer to a member, and returns a function 
			object suitable for use with standard or user-defined algorithms:
		</p>
		<pre>
struct X
{
    void f();
};

void g(std::vector&lt;X&gt; &amp; v)
{
    std::for_each(v.begin(), v.end(), boost::mem_fn(&amp;X::f));
};

void h(std::vector&lt;X *&gt; const &amp; v)
{
    std::for_each(v.begin(), v.end(), boost::mem_fn(&amp;X::f));
};

void k(std::vector&lt;boost::shared_ptr&lt;X&gt; &gt; const &amp; v)
{
    std::for_each(v.begin(), v.end(), boost::mem_fn(&amp;X::f));
};
</pre>
		<p>
			The returned function object takes the same arguments as the input member 
			function plus a "flexible" first argument that represents the object instance.
		</p>
		<p>
			When the function object is invoked with a first argument <b>x</b> that is 
			neither a pointer nor a reference to the appropriate class (<b>X</b> in the 
			example above), it uses <tt>get_pointer(x)</tt> to obtain a pointer from <b>x</b>. 
			Library authors can "register" their smart pointer classes by supplying an 
			appropriate <b>get_pointer</b> overload, allowing <b>mem_fn</b> to recognize 
			and support them.
		</p>
		<p>
			[Note: <b>get_pointer</b> is not restricted to return a pointer. Any object 
			that can be used in a member function call expression <tt>(x-&gt;*pmf)(...)</tt>
			will work.]
		</p>
		<p>
			[Note: the library uses an unqualified call to <b>get_pointer</b>. Therefore, 
			it will find, through argument-dependent lookup, <b>get_pointer</b> overloads 
			that are defined in the same namespace as the corresponding smart pointer 
			class, in addition to any <b>boost::get_pointer</b> overloads.]
		</p>
		<p>
			All function objects returned by <b>mem_fn</b> expose a <b>result_type</b> typedef 
			that represents the return type of the member function. For data members, <STRONG>result_type</STRONG>
			is defined as the type of the member.
		</p>
		<h2><a name="FAQ">Frequently Asked Questions</a></h2>
		<h3><a name="Q1">Can <b>mem_fn</b> be used instead of the standard <b>std::mem_fun[_ref]</b>
				adaptors?</a></h3>
		<p>
			Yes. For simple uses, <b>mem_fn</b> provides additional functionality that the 
			standard adaptors do not. Complicated expressions that use <b>std::bind1st</b>, <b>std::bind2nd</b>
			or <a href="../compose/index.htm"><b>Boost.Compose</b></a> along with the 
			standard adaptors can be rewritten using <a href="bind.html"><b>boost::bind</b></a>
			that automatically takes advantage of <b>mem_fn</b>.
		</p>
		<h3><a name="Q2">Should I replace every occurence of <b>std::mem_fun[_ref]</b> with <b>mem_fn</b>
				in my existing code?</a></h3>
		<p>
			No, unless you have good reasons to do so. <b>mem_fn</b> is not 100% compatible 
			with the standard adaptors, although it comes pretty close. In particular, <b>mem_fn</b>
			does not return objects of type <b>std::[const_]mem_fun[1][_ref]_t</b>, as the 
			standard adaptors do, and it is not possible to fully describe the type of the 
			first argument using the standard <b>argument_type</b> and <b>first_argument_type</b>
			nested typedefs. Libraries that need adaptable function objects in order to 
			function might not like <b>mem_fn</b>.
		</p>
		<h3><a name="Q3">Does <b>mem_fn</b> work with COM methods?</a></h3>
		<p>
			Yes, if you <a href="#stdcall">#define BOOST_MEM_FN_ENABLE_STDCALL</a>.
		</p>
		<h3><a name="Q4">Why isn't BOOST_MEM_FN_ENABLE_STDCALL defined automatically?</a></h3>
		<p>
			Non-portable extensions, in general, should default to off to prevent vendor 
			lock-in. Had BOOST_MEM_FN_ENABLE_STDCALL been defined automatically, you could 
			have accidentally taken advantage of it without realizing that your code is, 
			perhaps, no longer portable. In addition, it is possible for the default 
			calling convention to be __stdcall, in which case enabling __stdcall support 
			will result in duplicate definitions.
		</p>
		<h2><a name="Interface">Interface</a></h2>
		<h3><a name="Synopsis">Synopsis</a></h3>
		<pre>
namespace boost
{

template&lt;class T&gt; T * <a href="#get_pointer_1">get_pointer</a>(T * p);

template&lt;class R, class T&gt; <i>unspecified-1</i> <a href="#mem_fn_1">mem_fn</a>(R (T::*pmf) ());

template&lt;class R, class T&gt; <i>unspecified-2</i> <a href="#mem_fn_2">mem_fn</a>(R (T::*pmf) () const);

template&lt;class R, class T&gt; <i>unspecified-2-1</i> <a href="#mem_fn_2_1">mem_fn</a>(R T::*pm);

template&lt;class R, class T, class A1&gt; <i>unspecified-3</i> <a href="#mem_fn_3">mem_fn</a>(R (T::*pmf) (A1));

template&lt;class R, class T, class A1&gt; <i>unspecified-4</i> <a href="#mem_fn_4">mem_fn</a>(R (T::*pmf) (A1) const);

template&lt;class R, class T, class A1, class A2&gt; <i>unspecified-5</i> <a href="#mem_fn_5">mem_fn</a>(R (T::*pmf) (A1, A2));

template&lt;class R, class T, class A1, class A2&gt; <i>unspecified-6</i> <a href="#mem_fn_6">mem_fn</a>(R (T::*pmf) (A1, A2) const);

// implementation defined number of additional overloads for more arguments

}
</pre>
		<h3><a name="CommonRequirements">Common requirements</a></h3>
		<p>
			All <tt><i>unspecified-N</i></tt> types mentioned in the Synopsis are <b>CopyConstructible</b>
			and <b>Assignable</b>. Their copy constructors and assignment operators do not 
			throw exceptions. <tt><i>unspecified-N</i>::result_type</tt> is defined as the 
			return type of the member function pointer passed as an argument to <b>mem_fn</b>
			(<b>R</b> in the Synopsis.) <tt><i>unspecified-2-1</i>::result_type</tt> is 
			defined as <tt>R</tt>.
		</p>
		<h3><a name="get_pointer">get_pointer</a></h3>
		<h4><a name="get_pointer_1">template&lt;class T&gt; T * get_pointer(T * p)</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> <tt>p</tt>.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h3><a name="mem_fn">mem_fn</a></h3>
		<h4><a name="mem_fn_1">template&lt;class R, class T&gt; <i>unspecified-1</i> mem_fn(R 
				(T::*pmf) ())</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t)</i></tt>
				is equivalent to <tt>(t.*pmf)()</tt> when <i>t</i> is an l-value of type <STRONG>T </STRONG>
				or derived, <tt>(get_pointer(t)-&gt;*pmf)()</tt> otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h4><a name="mem_fn_2">template&lt;class R, class T&gt; <i>unspecified-2</i> mem_fn(R 
				(T::*pmf) () const)</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t)</i></tt>
				is equivalent to <tt>(t.*pmf)()</tt> when <i>t</i> is of type <STRONG>T</STRONG>
				<EM>[const]<STRONG> </STRONG></EM>or derived, <tt>(get_pointer(t)-&gt;*pmf)()</tt>
				otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h4><a name="mem_fn_2_1">template&lt;class R, class T&gt; <i>unspecified-2-1</i> mem_fn(R 
				T::*pm)</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t)</i></tt>
				is equivalent to <tt>t.*pm</tt> when <i>t</i> is of type <STRONG>T</STRONG> <EM>[const]<STRONG>
					</STRONG></EM>or derived, <tt>get_pointer(t)-&gt;*pm</tt> otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h4><a name="mem_fn_3">template&lt;class R, class T, class A1&gt; <i>unspecified-3</i> mem_fn(R 
				(T::*pmf) (A1))</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t, a1)</i></tt>
				is equivalent to <tt>(t.*pmf)(a1)</tt> when <i>t</i> is an l-value of type <STRONG>T
				</STRONG>or derived, <tt>(get_pointer(t)-&gt;*pmf)(a1)</tt> otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h4><a name="mem_fn_4">template&lt;class R, class T, class A1&gt; <i>unspecified-4</i> mem_fn(R 
				(T::*pmf) (A1) const)</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t, a1)</i></tt>
				is equivalent to <tt>(t.*pmf)(a1)</tt> when <i>t</i> is of type <STRONG>T</STRONG>
				<EM>[const]<STRONG> </STRONG></EM>or derived, <tt>(get_pointer(t)-&gt;*pmf)(a1)</tt>
				otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h4><a name="mem_fn_5">template&lt;class R, class T, class A1, class A2&gt; <i>unspecified-5</i>
				mem_fn(R (T::*pmf) (A1, A2))</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t, a1, a2)</i></tt>
				is equivalent to <tt>(t.*pmf)(a1, a2)</tt> when <i>t</i> is an l-value of type <STRONG>
					T</STRONG> or derived, <tt>(get_pointer(t)-&gt;*pmf)(a1, a2)</tt> otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h4><a name="mem_fn_6">template&lt;class R, class T, class A1, class A2&gt; <i>unspecified-6</i>
				mem_fn(R (T::*pmf) (A1, A2) const)</a></h4>
		<blockquote>
			<p>
				<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t, a1, a2)</i></tt>
				is equivalent to <tt>(t.*pmf)(a1, a2)</tt> when <i>t</i> is of type <STRONG>T</STRONG>
				<EM>[const]</EM> or derived, <tt>(get_pointer(t)-&gt;*pmf)(a1, a2)</tt> otherwise.
			</p>
			<p>
				<b>Throws:</b> Nothing.
			</p>
		</blockquote>
		<h2><a name="Implementation">Implementation</a></h2>
		<h3><a name="Files">Files</a></h3>
		<ul>
			<li>
				<a href="../../boost/mem_fn.hpp">boost/mem_fn.hpp</a>
			(main header)
			<li>
				<a href="../../boost/bind/mem_fn_cc.hpp">boost/bind/mem_fn_cc.hpp</a>
			(used by mem_fn.hpp, do not include directly)
			<li>
				<a href="../../boost/bind/mem_fn_vw.hpp">boost/bind/mem_fn_vw.hpp</a>
			(used by mem_fn.hpp, do not include directly)
			<li>
				<a href="../../boost/bind/mem_fn_template.hpp">boost/bind/mem_fn_template.hpp</a>
			(used by mem_fn.hpp, do not include directly)
			<li>
				<a href="test/mem_fn_test.cpp">libs/bind/test/mem_fn_test.cpp</a>
			(test)
			<li>
				<a href="test/mem_fn_derived_test.cpp">libs/bind/test/mem_fn_derived_test.cpp</a>
			(test with derived objects)
			<li>
				<a href="test/mem_fn_fastcall_test.cpp">libs/bind/test/mem_fn_fastcall_test.cpp</a>
			(test for __fastcall)
			<li>
				<a href="test/mem_fn_stdcall_test.cpp">libs/bind/test/mem_fn_stdcall_test.cpp</a>
			(test for __stdcall)
			<li>
				<a href="test/mem_fn_void_test.cpp">libs/bind/test/mem_fn_void_test.cpp</a> (test 
				for void returns)</li>
		</ul>
		<h3><a name="Dependencies">Dependencies</a></h3>
		<ul>
			<li>
				<a href="../config/config.htm">Boost.Config</a></li>
		</ul>
		<h3><a name="NumberOfArguments">Number of Arguments</a></h3>
		<p>
			This implementation supports member functions with up to eight arguments. This 
			is not an inherent limitation of the design, but an implementation detail.
		</p>
		<h3><a name="stdcall">"__stdcall", "__cdecl" and "__fastcall" Support</a></h3>
		<p>
			Some platforms allow several types of member functions that differ by their <b>calling 
				convention</b> (the rules by which the function is invoked: how are 
			arguments passed, how is the return value handled, and who cleans up the stack 
			- if any.)
		</p>
		<p>
			For example, Windows API functions and COM interface member functions use a 
			calling convention known as <b>__stdcall</b>. Borland VCL components use <STRONG>__fastcall</STRONG>. 
			UDK, the component model of OpenOffice.org, uses <STRONG>__cdecl</STRONG>.
		</p>
		<p>
			To use <b>mem_fn</b> with <b>__stdcall</b> member functions, <b>#define</b> the 
			macro <b>BOOST_MEM_FN_ENABLE_STDCALL</b> before including, directly or 
			indirectly, <b>&lt;boost/mem_fn.hpp&gt;</b>.
		</p>
		<P>To use <B>mem_fn</B> with <B>__fastcall</B> member functions, <B>#define</B> the 
			macro <B>BOOST_MEM_FN_ENABLE_FASTCALL</B> before including <B>&lt;boost/mem_fn.hpp&gt;</B>.
		</P>
		<P>To use <B>mem_fn</B> with <B>__cdecl</B> member functions, <B>#define</B> the 
			macro <B>BOOST_MEM_FN_ENABLE_CDECL</B> before including <B>&lt;boost/mem_fn.hpp&gt;</B>.
		</P>
		<P><STRONG>It is best to define these macros in the project options, via -D on the 
				command line, or as the first line in the translation unit (.cpp file) where 
				mem_fn is used.</STRONG> Not following this rule can lead to obscure errors 
			when a header includes mem_fn.hpp before the macro has been defined.</P>
		<P>[Note: this is a non-portable extension. It is not part of the interface.]
		</P>
		<p>
			[Note: Some compilers provide only minimal support for the <b>__stdcall</b> keyword.]
		</p>
		<h2><a name="Acknowledgements">Acknowledgements</a></h2>
		<p>
			Rene Jager's initial suggestion of using traits classes to make <b>mem_fn</b> adapt 
			to user-defined smart pointers inspired the <b>get_pointer</b>-based design.
		</p>
		<p>
			Numerous improvements were suggested during the formal review period by Richard 
			Crossley, Jens Maurer, Ed Brey, and others. Review manager was Darin Adler.
		</p>
		<p>
			Steve Anichini pointed out that COM interfaces use <b>__stdcall</b>.
		</p>
		<p>
			Dave Abrahams modified <b>bind</b> and <b>mem_fn</b> to support void returns on 
			deficient compilers.
		</p>
		<p>Daniel Boelzle pointed out that UDK uses <STRONG>__cdecl</STRONG>.<br>
			<br>
			<br>
			<small>Copyright © 2001, 2002 by Peter Dimov and Multi Media Ltd. Copyright 
				2003-2005 Peter Dimov. Distributed under the Boost Software License, Version 
				1.0. See accompanying file <A href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</A> or 
				copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>.</small></p>
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