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source: downloads/boost_1_33_1/libs/bind/bind.html @ 12

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[12]	1	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
	2	<html>
	3	<head>
	4	<title>Boost: bind.hpp documentation</title>
	5	<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
	6	</head>
	7	<body style="MARGIN-LEFT: 5%; MARGIN-RIGHT: 5%" bgColor="white">
	8	<table width="100%" border="0">
	9	<tr>
	10	<td width="277"><IMG height="86" alt="boost.png (6897 bytes)" src="../../boost.png" width="277">
	11	</td>
	12	<td align="center">
	13	<h1>bind.hpp</h1>
	14	</td>
	15	</tr>
	16	<tr>
	17	<td colSpan="2" height="64"> </td>
	18	</tr>
	19	</table>
	20	<h2>Contents</h2>
	21	<h3 style="MARGIN-LEFT: 20pt"><A href="#Purpose">Purpose</A></h3>
	22	<h4 style="MARGIN-LEFT: 40pt"><A href="#with_functions">Using bind with functions and
	23	function pointers</A></h4>
	24	<h4 style="MARGIN-LEFT: 40pt"><A href="#with_function_objects">Using bind with function
	25	objects</A></h4>
	26	<h4 style="MARGIN-LEFT: 40pt"><A href="#with_member_pointers">Using bind with pointers
	27	to members</A></h4>
	28	<h4 style="MARGIN-LEFT: 40pt"><A href="#nested_binds">Using nested binds for function
	29	composition</A></h4>
	30	<h4 style="MARGIN-LEFT: 40pt"><A href="#operators">Overloaded operators</A></h4>
	31	<h3 style="MARGIN-LEFT: 20pt"><A href="#Examples">Examples</A></h3>
	32	<h4 style="MARGIN-LEFT: 40pt"><A href="#with_algorithms">Using bind with standard
	33	algorithms</A></h4>
	34	<h4 style="MARGIN-LEFT: 40pt"><A href="#with_boost_function">Using bind with
	35	Boost.Function</A></h4>
	36	<h3 style="MARGIN-LEFT: 20pt"><A href="#Limitations">Limitations</A></h3>
	37	<h3 style="MARGIN-LEFT: 20pt"><A href="#FAQ">Frequently Asked Questions</A></h3>
	38	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_doesnt_compile">Why doesn't this compile?</A></h4>
	39	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_does_compile">Why does this compile? It
	40	should not.</A></h4>
	41	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_forms">What is the difference between bind(f,
	42	...) and bind<R>(f, ...)?</A></h4>
	43	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_win32_api">Does <b>bind</b> work with Windows
	44	API functions?</A></h4>
	45	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_com">Does <b>bind</b> work with COM methods?</A></h4>
	46	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_mac">Does <b>bind</b> work with Mac toolbox
	47	functions?</A></h4>
	48	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_extern_C">Does <b>bind</b> work with extern
	49	"C" functions?</A></h4>
	50	<h4 style="MARGIN-LEFT: 40pt"><A href="#Q_auto_stdcall">Why doesn't <b>bind</b> automatically
	51	recognize nonstandard functions?</A></h4>
	52	<h3 style="MARGIN-LEFT: 20pt"><A href="#Troubleshooting">Troubleshooting</A></h3>
	53	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_num_args">Incorrect number of arguments</A></h4>
	54	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_signature">The function object cannot be
	55	called with the specified arguments</A></h4>
	56	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_arg_access">Accessing an argument that does
	57	not exist</A></h4>
	58	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_short_form">Inappropriate use of bind(f,
	59	...)</A></h4>
	60	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_long_form">Inappropriate use of
	61	bind<R>(f, ...)</A></h4>
	62	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_nonstd">Binding a nonstandard function</A></h4>
	63	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_const_arg"><b>const</b> in signatures</A></h4>
	64	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_msvc_using">MSVC specific: using
	65	boost::bind;</A></h4>
	66	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_msvc_class_template">MSVC specific: class
	67	templates shadow function templates</A></h4>
	68	<h4 style="MARGIN-LEFT: 40pt"><A href="#err_msvc_ellipsis">MSVC specific: ... in
	69	signatures treated as type</A></h4>
	70	<h3 style="MARGIN-LEFT: 20pt"><A href="#Interface">Interface</A></h3>
	71	<h4 style="MARGIN-LEFT: 40pt"><A href="#Synopsis">Synopsis</A></h4>
	72	<h4 style="MARGIN-LEFT: 40pt"><A href="#CommonRequirements">Common requirements</A></h4>
	73	<h4 style="MARGIN-LEFT: 40pt"><A href="#CommonDefinitions">Common definitions</A></h4>
	74	<h4 style="MARGIN-LEFT: 40pt"><A href="#bind">bind</A></h4>
	75	<h4 style="MARGIN-LEFT: 40pt"><A href="#AdditionalOverloads">Additional overloads</A></h4>
	76	<h3 style="MARGIN-LEFT: 20pt"><A href="#Implementation">Implementation</A></h3>
	77	<h4 style="MARGIN-LEFT: 40pt"><A href="#Files">Files</A></h4>
	78	<h4 style="MARGIN-LEFT: 40pt"><A href="#Dependencies">Dependencies</A></h4>
	79	<h4 style="MARGIN-LEFT: 40pt"><A href="#NumberOfArguments">Number of Arguments</A></h4>
	80	<h4 style="MARGIN-LEFT: 40pt"><A href="#stdcall">"__stdcall", "__cdecl", "__fastcall",
	81	and "pascal" Support</A></h4>
	82	<h4 style="MARGIN-LEFT: 40pt"><A href="#visit_each"><b>visit_each</b> support</A></h4>
	83	<h3 style="MARGIN-LEFT: 20pt"><A href="#Acknowledgements">Acknowledgements</A></h3>
	84	<h2><a name="Purpose">Purpose</a></h2>
	85	<p><b>boost::bind</b> is a generalization of the standard functions <b>std::bind1st</b>
	86	and <b>std::bind2nd</b>. It supports arbitrary function objects, functions,
	87	function pointers, and member function pointers, and is able to bind any
	88	argument to a specific value or route input arguments into arbitrary positions. <b>bind</b>
	89	does not place any requirements on the function object; in particular, it does
	90	not need the <b>result_type</b>, <b>first_argument_type</b> and <b>second_argument_type</b>
	91	standard typedefs.
	92	</p>
	93	<h3><a name="with_functions">Using bind with functions and function pointers</a></h3>
	94	<p>Given these definitions:
	95	</p>
	96	<pre>int f(int a, int b)
	97	{
	98	return a + b;
	99	}
	100
	101	int g(int a, int b, int c)
	102	{
	103	return a + b + c;
	104	}
	105	</pre>
	106	<p><tt>bind(f, 1, 2)</tt> will produce a "nullary" function object that takes no
	107	arguments and returns <tt>f(1, 2)</tt>. Similarly, <tt>bind(g, 1, 2, 3)()</tt> is
	108	equivalent to <tt>g(1, 2, 3)</tt>.
	109	</p>
	110	<p>It is possible to selectively bind only some of the arguments. <tt>bind(f, _1, 5)(x)</tt>
	111	is equivalent to <tt>f(x, 5)</tt>; here <b>_1</b>
	112	is a placeholder argument that means "substitute with the first input
	113	argument."
	114	<p>For comparison, here is the same operation expressed with the standard library
	115	primitives:
	116	</p>
	117	<pre>std::bind2nd(std::ptr_fun(f), 5)(x);
	118	</pre>
	119	<p><b>bind</b> covers the functionality of <b>std::bind1st</b> as well:
	120	</p>
	121	<pre>std::bind1st(std::ptr_fun(f), 5)(x); // f(5, x)
	122	bind(f, 5, _1)(x); // f(5, x)
	123	</pre>
	124	<p><b>bind</b> can handle functions with more than two arguments, and its argument
	125	substitution mechanism is more general:
	126	</p>
	127	<pre>bind(f, _2, _1)(x, y); // f(y, x)
	128
	129	bind(g, _1, 9, _1)(x); // g(x, 9, x)
	130
	131	bind(g, _3, _3, _3)(x, y, z); // g(z, z, z)
	132
	133	bind(g, _1, _1, _1)(x, y, z); // g(x, x, x)
	134	</pre>
	135	<p>Note that, in the last example, the function object produced by <tt>bind(g, _1, _1,
	136	_1)</tt> does not contain references to any arguments beyond the first, but
	137	it can still be used with more than one argument. Any extra arguments are
	138	silently ignored, just like the first and the second argument are ignored in
	139	the third example.
	140	</p>
	141	<p>The arguments that <b>bind</b> takes are copied and held internally by the
	142	returned function object. For example, in the following code:
	143	</p>
	144	<pre>int i = 5;
	145
	146	bind(f, i, _1);
	147	</pre>
	148	<p>a copy of the value of <b>i</b> is stored into the function object. <A href="ref.html">
	149	boost::ref</A> and <A href="ref.html">boost::cref</A> can be used to make
	150	the function object store a reference to an object, rather than a copy:
	151	</p>
	152	<pre>int i = 5;
	153
	154	bind(f, ref(i), _1);
	155
	156	bind(f, cref(42), _1);
	157	</pre>
	158	<h3><a name="with_function_objects">Using bind with function objects</a></h3>
	159	<p><b>bind</b> is not limited to functions; it accepts arbitrary function objects.
	160	In the general case, the return type of the generated function object's <b>operator()</b>
	161	has to be specified explicitly (without a <b>typeof</b> operator the return
	162	type cannot be inferred):
	163	</p>
	164	<pre>struct F
	165	{
	166	int operator()(int a, int b) { return a - b; }
	167	bool operator()(long a, long b) { return a == b; }
	168	};
	169
	170	F f;
	171
	172	int x = 104;
	173
	174	bind<int>(f, _1, _1)(x); // f(x, x), i.e. zero
	175	</pre>
	176	<p>Some compilers have trouble with the <tt>bind<R>(f, ...)</tt> syntax. For
	177	portability reasons, an alternative way to express the above is supported:</p>
	178	<pre>boost::bind(boost::type<int>(), f, _1, _1)(x);
	179	</pre>
	180	<P>Note, however, that the alternative syntax is provided only as a workaround. It
	181	is not part of the interface.</P>
	182	<P>When the function object exposes a nested type named <b>result_type</b>, the
	183	explicit return type can be omitted:
	184	</P>
	185	<pre>int x = 8;
	186
	187	bind(std::less<int>(), _1, 9)(x); // x < 9
	188	</pre>
	189	<p>[Note: the ability to omit the return type is not available on all compilers.]
	190	</p>
	191	<h3><a name="with_member_pointers">Using bind with pointers to members</a></h3>
	192	<p>Pointers to member functions and pointers to data members are not function
	193	objects, because they do not support <tt>operator()</tt>. For convenience, <b>bind</b>
	194	accepts member pointers as its first argument, and the behavior is as if <A href="mem_fn.html">
	195	boost::mem_fn</A> has been used to convert the member pointer into a
	196	function object. In other words, the expression
	197	</p>
	198	<pre>bind(&X::f, <i>args</i>)
	199	</pre>
	200	<p>is equivalent to
	201	</p>
	202	<pre>bind<R>(<A href="mem_fn.html" >mem_fn</A>(&X::f), <i>args</i>)
	203	</pre>
	204	<p>where <b>R</b> is the return type of <b>X::f</b> (for member functions) or the
	205	type of the member (for data members.)
	206	</p>
	207	<p>[Note: <b>mem_fn</b> creates function objects that are able to accept a pointer,
	208	a reference, or a smart pointer to an object as its first argument; for
	209	additional information, see the <b>mem_fn</b> <A href="mem_fn.html">documentation</A>.]
	210	</p>
	211	<p>Example:
	212	</p>
	213	<pre>struct X
	214	{
	215	bool f(int a);
	216	};
	217
	218	X x;
	219
	220	shared_ptr<X> p(new X);
	221
	222	int i = 5;
	223
	224	bind(&X::f, ref(x), _1)(i); // x.f(i)
	225	bind(&X::f, &x, _1)(i); //(&x)->f(i)
	226	bind(&X::f, x, _1)(i); // (<i>internal copy of x</i>).f(i)
	227	bind(&X::f, p, _1)(i); // (<i>internal copy of p</i>)->f(i)
	228	</pre>
	229	<p>The last two examples are interesting in that they produce "self-contained"
	230	function objects. <tt>bind(&X::f, x, _1)</tt> stores a copy of <b>x</b>. <tt>bind(&X::f,
	231	p, _1)</tt> stores a copy of <b>p</b>, and since <b>p</b> is a <A href="../smart_ptr/shared_ptr.htm">
	232	boost::shared_ptr</A>, the function object retains a reference to its
	233	instance of <b>X</b> and will remain valid even when <b>p</b> goes out of scope
	234	or is <b>reset()</b>.
	235	</p>
	236	<h3><a name="nested_binds">Using nested binds for function composition</a></h3>
	237	<p>Some of the arguments passed to <b>bind</b> may be nested <b>bind</b> expressions
	238	themselves:
	239	</p>
	240	<pre>bind(f, bind(g, _1))(x); // f(g(x))
	241	</pre>
	242	<p>The inner <STRONG>bind</STRONG> expressions are evaluated, in unspecified order,
	243	before the outer <STRONG>bind</STRONG> when the function object is called; the
	244	results of the evaluation are then substituted in their place when the outer <STRONG>
	245	bind</STRONG> is evaluated. In the example above, when the function object
	246	is called with the argument list <tt>(x)</tt>, <tt>bind(g, _1)(x)</tt> is
	247	evaluated first, yielding <tt>g(x)</tt>, and then <tt>bind(f, g(x))(x)</tt> is
	248	evaluated, yielding the final result <tt>f(g(x))</tt>.
	249	</p>
	250	<P>This feature of <b>bind</b> can be used to perform function composition. See <A href="bind_as_compose.cpp">
	251	bind_as_compose.cpp</A> for an example that demonstrates how to use <b>bind</b>
	252	to achieve similar functionality to <A href="../compose/index.htm">Boost.Compose</A>.
	253	</P>
	254	<p>Note that the first argument - the bound function object - is not evaluated,
	255	even when it's a function object that is produced by <STRONG>bind</STRONG> or a
	256	placeholder argument, so the example below does not work as expected:
	257	</p>
	258	<pre>typedef void (*pf)(int);
	259
	260	std::vector<pf> v;
	261
	262	std::for_each(v.begin(), v.end(), bind(_1, 5));
	263	</pre>
	264	<p>The desired effect can be achieved via a helper function object <STRONG>apply</STRONG>
	265	that applies its first argument, as a function object, to the rest of its
	266	argument list. For convenience, an implementation of <STRONG>apply</STRONG> is
	267	provided in the <STRONG>boost/bind/apply.hpp</STRONG> header file. Here is how
	268	the modified version of the previous example looks like:
	269	</p>
	270	<pre>typedef void (*pf)(int);
	271
	272	std::vector<pf> v;
	273
	274	std::for_each(v.begin(), v.end(), bind(apply<void>(), _1, 5));
	275	</pre>
	276	<P>Although the first argument is, by default, not evaluated, all other arguments
	277	are. Sometimes it is necessary not to evaluate arguments subsequent to the
	278	first, even when they are nested <STRONG>bind</STRONG> subexpressions. This can
	279	be achieved with the help of another function object, <STRONG>protect</STRONG>,
	280	that masks the type so that <STRONG>bind</STRONG> does not recognize and
	281	evaluate it. When called, <STRONG>protect</STRONG> simply forwards the argument
	282	list to the other function object unmodified.</P>
	283	<P>The header <STRONG>boost/bind/protect.hpp</STRONG> contains an implementation of <STRONG>
	284	protect</STRONG>. To protect a <STRONG>bind</STRONG> function object from
	285	evaluation, use <tt>protect(bind(f, ...))</tt>.</P>
	286	<h3><a name="operators">Overloaded operators</a> (new in Boost 1.33)</h3>
	287	<p>For convenience, the function objects produced by <tt>bind</tt> overload
	288	the logical not operator <STRONG>!</STRONG> and the relational operators <STRONG>==</STRONG>,
	289	<STRONG>!=</STRONG>, <STRONG><</STRONG>, <STRONG><=</STRONG>, <STRONG>></STRONG>,
	290	<STRONG>>=</STRONG>.</p>
	291	<P><tt>!bind(f, ...)</tt> is equivalent to <tt>bind( <EM>logical_not</EM>(), bind(f,
	292	...) )</tt>, where <tt><EM>logical_not</EM></tt> is a function object that
	293	takes one argument <tt>x</tt> and returns <tt>!x</tt>.</P>
	294	<P><tt>bind(f, ...) <EM>op</EM> x</tt>, where <EM>op</EM> is a relational operator,
	295	is equivalent to <tt>bind( <EM>relation</EM>(), bind(f, ...), x )</tt>, where <em>relation</em>
	296	is a function object that takes two arguments <tt>a</tt> and <tt>b</tt> and
	297	returns <tt>a <EM>op</EM> b</tt>.</P>
	298	<P>What this means in practice is that you can conveniently negate the result of
	299	<tt>bind</tt>:</P>
	300	<P><tt>std::remove_if( first, last, !bind( &X::visible, _1 ) ); // remove invisible
	301	objects</tt></P>
	302	<P>and compare the result of <tt>bind</tt> against a value:</P>
	303	<P><tt>std::find_if( first, last, bind( &X::name, _1 ) == "peter" );</tt></P>
	304	<P>against a placeholder:</P>
	305	<P><tt>bind( &X::name, _1 ) == _2</tt></P>
	306	<P>or against another <tt>bind</tt> expression:</P>
	307	<P><tt>std::sort( first, last, bind( &X::name, _1 ) < bind( &X::name, _2 )
	308	); // sort by name</tt></P>
	309	<h2><a name="Examples">Examples</a></h2>
	310	<h3><a name="with_algorithms">Using bind with standard algorithms</a></h3>
	311	<pre>class image;
	312
	313	class animation
	314	{
	315	public:
	316
	317	void advance(int ms);
	318	bool inactive() const;
	319	void render(image & target) const;
	320	};
	321
	322	std::vector<animation> anims;
	323
	324	template<class C, class P> void erase_if(C & c, P pred)
	325	{
	326	c.erase(std::remove_if(c.begin(), c.end(), pred), c.end());
	327	}
	328
	329	void update(int ms)
	330	{
	331	std::for_each(anims.begin(), anims.end(), boost::bind(&animation::advance, _1, ms));
	332	erase_if(anims, boost::mem_fn(&animation::inactive));
	333	}
	334
	335	void render(image & target)
	336	{
	337	std::for_each(anims.begin(), anims.end(), boost::bind(&animation::render, _1, boost::ref(target)));
	338	}
	339	</pre>
	340	<h3><a name="with_boost_function">Using bind with Boost.Function</a></h3>
	341	<pre>class button
	342	{
	343	public:
	344
	345	<A href="../function/index.html" >boost::function</A><void> onClick;
	346	};
	347
	348	class player
	349	{
	350	public:
	351
	352	void play();
	353	void stop();
	354	};
	355
	356	button playButton, stopButton;
	357	player thePlayer;
	358
	359	void connect()
	360	{
	361	playButton.onClick = boost::bind(&player::play, &thePlayer);
	362	stopButton.onClick = boost::bind(&player::stop, &thePlayer);
	363	}
	364	</pre>
	365	<h2><a name="Limitations">Limitations</a></h2>
	366	<p>The function objects generated by <b>bind</b> take their arguments by reference
	367	and cannot, therefore, accept non-const temporaries or literal constants. This
	368	is an inherent limitation of the C++ language, known as <A href="http://std.dkuug.dk/jtc1/sc22/wg21/docs/papers/2002/n1385.htm">
	369	the forwarding problem</A>.</p>
	370	<p>The library uses signatures of the form
	371	</p>
	372	<pre>template<class T> void f(T & t);
	373	</pre>
	374	<p>to accept arguments of arbitrary types and pass them on unmodified. As noted,
	375	this does not work with non-const r-values.
	376	</p>
	377	<p>An oft-proposed "solution" to this problem is to add an overload:
	378	</p>
	379	<pre>template<class T> void f(T & t);
	380	template<class T> void f(T const & t);
	381	</pre>
	382	<p>Unfortunately, this (a) requires providing 512 overloads for nine arguments and
	383	(b) does not actually work for const arguments, both l- and r-values, since the
	384	two templates produce the exact same signature and cannot be partially ordered.
	385	</p>
	386	<p>[Note: this is a dark corner of the language, and the <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#214">
	387	corresponding issue</a> has only recently been resolved.]
	388	</p>
	389	<h2><a name="FAQ">Frequently Asked Questions</a></h2>
	390	<h3><a name="Q_doesnt_compile">Why doesn't this compile?</a></h3>
	391	<p>See the <A href="#Troubleshooting">dedicated Troubleshooting section</A>.</p>
	392	<h3><a name="Q_does_compile">Why does this compile? It should not.</a></h3>
	393	<p>Probably because you used the general <tt>bind<R>(f, ...)</tt> syntax,
	394	thereby instructing <b>bind</b> to not "inspect" <b>f</b> to detect arity and
	395	return type errors.</p>
	396	<h3><a name="Q_forms">What is the difference between bind(f, ...) and bind<R>(f,
	397	...)?</a></h3>
	398	<p>The first form instructs <b>bind</b> to inspect the type of <b>f</b> in order to
	399	determine its arity (number of arguments) and return type. Arity errors will be
	400	detected at "bind time". This syntax, of course, places some requirements on <b>f</b>.
	401	It must be a function, function pointer, member function pointer, or a function
	402	object that defines a nested type named <b>result_type</b>; in short, it must
	403	be something that <b>bind</b> can recognize.</p>
	404	<p>The second form instructs <b>bind</b> to <b>not</b> attempt to recognize the
	405	type of <b>f</b>. It is generally used with function objects that do not, or
	406	cannot, expose <b>result_type</b>, but it can also be used with nonstandard
	407	functions. For example, the current implementation does not automatically
	408	recognize variable-argument functions like <b>printf</b>, so you will have to
	409	use <tt>bind<int>(printf, ...)</tt>. Note that an alternative <tt>bind(type<R>(),
	410	f, ...)</tt> syntax is supported for portability reasons.</p>
	411	<p>Another important factor to consider is that compilers without partial template
	412	specialization or function template partial ordering support cannot handle the
	413	first form when <b>f</b> is a function object, and in most cases will not
	414	handle the second form when <b>f</b> is a function (pointer) or a member
	415	function pointer.</p>
	416	<h3><a name="Q_win32_api">Does <b>bind</b> work with Windows API functions?</a></h3>
	417	<p>Yes, if you <A href="#stdcall">#define BOOST_BIND_ENABLE_STDCALL</A>. An
	418	alternative is to treat the function as a <A href="#with_function_objects">generic
	419	function object</A> and use the <tt>bind<R>(f, ...)</tt> syntax.</p>
	420	<h3><a name="Q_com">Does <b>bind</b> work with COM methods?</a></h3>
	421	<p>Yes, if you <A href="#stdcall">#define BOOST_MEM_FN_ENABLE_STDCALL</A>.</p>
	422	<h3><a name="Q_mac">Does <b>bind</b> work with Mac toolbox functions?</a></h3>
	423	<p>Yes, if you <A href="#stdcall">#define BOOST_BIND_ENABLE_PASCAL</A>. An
	424	alternative is to treat the function as a <A href="#with_function_objects">generic
	425	function object</A> and use the <tt>bind<R>(f, ...)</tt> syntax.</p>
	426	<h3><a name="Q_extern_C">Does <b>bind</b> work with extern "C" functions?</a></h3>
	427	<p>Sometimes. On some platforms, pointers to extern "C" functions are equivalent to
	428	"ordinary" function pointers, so they work fine. Other platforms treat them as
	429	different types. A platform-specific implementation of <b>bind</b> is expected
	430	to handle the problem transparently; this implementation does not. As usual,
	431	the workaround is to treat the function as a <A href="#with_function_objects">generic
	432	function object</A> and use the <tt>bind<R>(f, ...)</tt> syntax.</p>
	433	<h3><a name="Q_auto_stdcall">Why doesn't <b>bind</b> automatically recognize
	434	nonstandard functions?</a></h3>
	435	<p>Non-portable extensions, in general, should default to off to prevent vendor
	436	lock-in. Had the <A href="#stdcall">appropriate macros</A> been defined
	437	automatically, you could have accidentally taken advantage of them without
	438	realizing that your code is, perhaps, no longer portable. In addition, some
	439	compilers have the option to make <b>__stdcall</b> (<STRONG>__fastcall</STRONG>)
	440	their default calling convention, in which case no separate support would be
	441	necessary.</p>
	442	<h2><a name="Troubleshooting">Troubleshooting</a></h2>
	443	<h3><a name="err_num_args">Incorrect number of arguments</a></h3>
	444	<p>In a <tt>bind(f, a1, a2, ..., aN)</tt> expression, the function object <b>f</b> must
	445	be able to take exactly <b>N</b> arguments. This error is normally detected at
	446	"bind time"; in other words, the compilation error is reported on the line
	447	where bind() is invoked:</p>
	448	<pre>int f(int, int);
	449
	450	int main()
	451	{
	452	boost::bind(f, 1); // error, f takes two arguments
	453	boost::bind(f, 1, 2); // OK
	454	}
	455	</pre>
	456	<p>A common variation of this error is to forget that member functions have an
	457	implicit "this" argument:</p>
	458	<pre>struct X
	459	{
	460	int f(int);
	461	}
	462
	463	int main()
	464	{
	465	boost::bind(&X::f, 1); // error, X::f takes two arguments
	466	boost::bind(&X::f, <b>_1</b>, 1); // OK
	467	}
	468	</pre>
	469	<h3><a name="err_signature">The function object cannot be called with the specified
	470	arguments</a></h3>
	471	<p>As in normal function calls, the function object that is bound must be
	472	compatible with the argument list. The incompatibility will usually be detected
	473	by the compiler at "call time" and the result is typically an error in <b>bind.hpp</b>
	474	on a line that looks like:</p>
	475	<pre> return f(a[a1_], a[a2_]);
	476	</pre>
	477	<p>An example of this kind of error:</p>
	478	<pre>int f(int);
	479
	480	int main()
	481	{
	482	boost::bind(f, "incompatible"); // OK so far, no call
	483	boost::bind(f, "incompatible")(); // error, "incompatible" is not an int
	484	boost::bind(f, _1); // OK
	485	boost::bind(f, _1)("incompatible"); // error, "incompatible" is not an int
	486	}
	487	</pre>
	488	<h3><a name="err_arg_access">Accessing an argument that does not exist</a></h3>
	489	<p>The placeholder <b>_N</b> selects the argument at position <b>N</b> from the
	490	argument list passed at "call time." Naturally, it is an error to attempt to
	491	access beyond the end of this list:</p>
	492	<pre>int f(int);
	493
	494	int main()
	495	{
	496	boost::bind(f, _1); // OK
	497	boost::bind(f, _1)(); // error, there is no argument number 1
	498	}
	499	</pre>
	500	<p>The error is usually reported in <b>bind.hpp</b>, at a line similar to:</p>
	501	<pre> return f(a[a1_]);
	502	</pre>
	503	<p>When emulating <tt>std::bind1st(f, a)</tt>, a common mistake of this category is
	504	to type <tt>bind(f, a, _2)</tt> instead of the correct <tt>bind(f, a, _1)</tt>.</p>
	505	<h3><a name="err_short_form">Inappropriate use of bind(f, ...)</a></h3>
	506	<p>The <tt>bind(f, a1, a2, ..., aN)</tt> <A href="#Q_forms">form</A> causes
	507	automatic recognition of the type of <b>f</b>. It will not work with arbitrary
	508	function objects; <b>f</b> must be a function or a member function pointer.</p>
	509	<p>It is possible to use this form with function objects that define <b>result_type</b>,
	510	but <b>only on compilers</b> that support partial specialization and partial
	511	ordering. In particular, MSVC up to version 7.0 does not support this syntax
	512	for function objects.</p>
	513	<h3><a name="err_long_form">Inappropriate use of bind<R>(f, ...)</a></h3>
	514	<p>The <tt>bind<R>(f, a1, a2, ..., aN)</tt> <A href="#Q_forms">form</A> supports
	515	arbitrary function objects.</p>
	516	<p>It is possible (but not recommended) to use this form with functions or member
	517	function pointers, but <b>only on compilers</b> that support partial ordering.
	518	In particular, MSVC up to version 7.0 does not fully support this syntax for
	519	functions and member function pointers.</p>
	520	<h3><a name="err_nonstd">Binding a nonstandard function</a></h3>
	521	<p>By default, the <tt>bind(f, a1, a2, ..., aN)</tt> <A href="#Q_forms">form</A> recognizes
	522	"ordinary" C++ functions and function pointers. <A href="#stdcall">Functions that
	523	use a different calling convention</A>, or variable-argument functions such
	524	as <STRONG>std::printf</STRONG>, do not work. The general <tt>bind<R>(f, a1,
	525	a2, ..., aN)</tt> <A href="#Q_forms">form</A> works with nonstandard
	526	functions.
	527	</p>
	528	<p>On some platforms, extern "C" functions, like <b>std::strcmp</b>, are not
	529	recognized by the short form of bind.
	530	</p>
	531	<P>See also <A href="#stdcall">"__stdcall" and "pascal" Support</A>.</P>
	532	<h3><a name="err_const_arg"><b>const</b> in signatures</a></h3>
	533	<p>Some compilers, including MSVC 6.0 and Borland C++ 5.5.1, have problems with the
	534	top-level <b>const</b> in function signatures:
	535	</p>
	536	<pre>int f(int const);
	537
	538	int main()
	539	{
	540	boost::bind(f, 1); // error
	541	}
	542	</pre>
	543	<p>Workaround: remove the <b>const</b> qualifier from the argument.
	544	</p>
	545	<h3><a name="err_msvc_using">MSVC specific: using boost::bind;</a></h3>
	546	<p>On MSVC (up to version 7.0), when <b>boost::bind</b> is brought into scope with
	547	an using declaration:
	548	</p>
	549	<pre>using boost::bind;
	550	</pre>
	551	<p>the syntax <tt>bind<R>(f, ...)</tt> does not work. Workaround: either use
	552	the qualified name, <b>boost::bind</b>, or use an using directive instead:
	553	</p>
	554	<pre>using namespace boost;
	555	</pre>
	556	<h3><a name="err_msvc_class_template">MSVC specific: class templates shadow function
	557	templates</a></h3>
	558	<p>On MSVC (up to version 7.0), a nested class template named <b>bind</b> will
	559	shadow the function template <b>boost::bind</b>, breaking the <tt>bind<R>(f,
	560	...)</tt> syntax. Unfortunately, some libraries contain nested class
	561	templates named <b>bind</b> (ironically, such code is often an MSVC specific
	562	workaround.)</p>
	563	<P>The workaround is to use the alternative <tt>bind(type<R>(), f, ...)</tt> syntax.</P>
	564	<h3><a name="err_msvc_ellipsis">MSVC specific: ... in signatures treated as type</a></h3>
	565	<p>MSVC (up to version 7.0) treats the ellipsis in a variable argument function
	566	(such as <b>std::printf</b>) as a type. Therefore, it will accept the
	567	(incorrect in the current implementation) form:
	568	</p>
	569	<pre> bind(printf, "%s\n", _1);
	570	</pre>
	571	<p>and will reject the correct version:
	572	</p>
	573	<pre> bind<int>(printf, "%s\n", _1);
	574	</pre>
	575	<h2><a name="Interface">Interface</a></h2>
	576	<h3><a name="Synopsis">Synopsis</a></h3>
	577	<pre>namespace boost
	578	{
	579
	580	// no arguments
	581
	582	template<class R, class F> <i>unspecified-1</i> <A href="#bind_1" >bind</A>(F f);
	583
	584	template<class F> <i>unspecified-1-1</i> <A href="#bind_1_1" >bind</A>(F f);
	585
	586	template<class R> <i>unspecified-2</i> <A href="#bind_2" >bind</A>(R (*f) ());
	587
	588	// one argument
	589
	590	template<class R, class F, class A1> <i>unspecified-3</i> <A href="#bind_3" >bind</A>(F f, A1 a1);
	591
	592	template<class F, class A1> <i>unspecified-3-1</i> <A href="#bind_3_1" >bind</A>(F f, A1 a1);
	593
	594	template<class R, class B1, class A1> <i>unspecified-4</i> <A href="#bind_4" >bind</A>(R (*f) (B1), A1 a1);
	595
	596	template<class R, class T, class A1> <i>unspecified-5</i> <A href="#bind_5" >bind</A>(R (T::*f) (), A1 a1);
	597
	598	template<class R, class T, class A1> <i>unspecified-6</i> <A href="#bind_6" >bind</A>(R (T::*f) () const, A1 a1);
	599
	600	template<class R, class T, class A1> <i>unspecified-6-1</i> <A href="#bind_6_1" >bind</A>(R T::*f, A1 a1);
	601
	602	// two arguments
	603
	604	template<class R, class F, class A1, class A2> <i>unspecified-7</i> <A href="#bind_7" >bind</A>(F f, A1 a1, A2 a2);
	605
	606	template<class F, class A1, class A2> <i>unspecified-7-1</i> <A href="#bind_7_1" >bind</A>(F f, A1 a1, A2 a2);
	607
	608	template<class R, class B1, class B2, class A1, class A2> <i>unspecified-8</i> <A href="#bind_8" >bind</A>(R (*f) (B1, B2), A1 a1, A2 a2);
	609
	610	template<class R, class T, class B1, class A1, class A2> <i>unspecified-9</i> <A href="#bind_9" >bind</A>(R (T::*f) (B1), A1 a1, A2 a2);
	611
	612	template<class R, class T, class B1, class A1, class A2> <i>unspecified-10</i> <A href="#bind_10" >bind</A>(R (T::*f) (B1) const, A1 a1, A2 a2);
	613
	614	// implementation defined number of additional overloads for more arguments
	615
	616	}
	617
	618	namespace
	619	{
	620
	621	<i>unspecified-placeholder-type-1</i> _1;
	622
	623	<i>unspecified-placeholder-type-2</i> _2;
	624
	625	<i>unspecified-placeholder-type-3</i> _3;
	626
	627	// implementation defined number of additional placeholder definitions
	628
	629	}
	630	</pre>
	631	<h3><a name="CommonRequirements">Common requirements</a></h3>
	632	<p>All <tt><i>unspecified-N</i></tt> types returned by <b>bind</b> are <b>CopyConstructible</b>.
	633	<tt><i>unspecified-N</i>::result_type</tt> is defined as the return type of <tt><i>unspecified-N</i>::operator()</tt>.</p>
	634	<p>All <tt><i>unspecified-placeholder-N</i></tt> types are <b>CopyConstructible</b>.
	635	Their copy constructors do not throw exceptions.</p>
	636	<h3><a name="CommonDefinitions">Common definitions</a></h3>
	637	<p>The function µ(x, v<sub>1</sub>, v<sub>2</sub>, ..., v<sub>m</sub>), where m is
	638	a nonnegative integer, is defined as:</p>
	639	<ul>
	640	<li>
	641	<tt>x.get()</tt>, when <tt>x</tt> is of type <tt><A href="ref.html">boost::reference_wrapper</A><T></tt>
	642	for some type <tt>T</tt>;
	643	<li>
	644	v<sub>k</sub>, when <tt>x</tt>
	645	is (a copy of) the placeholder _k for some positive integer k;
	646	<li>
	647	<tt>x(v<sub>1</sub>, v<sub>2</sub>, ..., v<sub>m</sub>)</tt> when <tt>x</tt> is
	648	(a copy of) a function object returned by <b>bind</b>;
	649	<li>
	650	<tt>x</tt> otherwise.</li></ul>
	651	<h3><a name="bind">bind</a></h3>
	652	<h4><a name="bind_1">template<class R, class F> <i>unspecified-1</i> bind(F f)</a></h4>
	653	<blockquote>
	654	<p><b>Returns:</b> A function object <i>λ</i> such that the expression <tt>λ(v<sub>1</sub>,
	655	v<sub>2</sub>, ..., v<sub>m</sub>)</tt> is equivalent to <tt><b>f</b>()</tt>,
	656	implicitly converted to <b>R</b>.</p>
	657	<p><b>Throws:</b> Nothing unless the copy constructor of <b>F</b> throws an
	658	exception.</p>
	659	</blockquote>
	660	<h4><a name="bind_1_1">template<class F> <i>unspecified-1-1</i> bind(F f)</a></h4>
	661	<blockquote>
	662	<p><b>Effects:</b> Equivalent to <tt>bind<typename F::result_type, F>(f);</tt></p>
	663	<p><b>Notes:</b> Implementations are allowed to infer the return type of <b>f</b> via
	664	other means as an extension, without relying on the <tt>result_type</tt> member.</p>
	665	</blockquote>
	666	<h4><a name="bind_2">template<class R> <i>unspecified-2</i> bind(R (*f) ())</a></h4>
	667	<blockquote>
	668	<p><b>Returns:</b> A function object <i>λ</i> such that the expression <tt>λ(v<sub>1</sub>,
	669	v<sub>2</sub>, ..., v<sub>m</sub>)</tt> is equivalent to <tt><b>f</b>()</tt>.</p>
	670	<p><b>Throws:</b> Nothing.</p>
	671	</blockquote>
	672	<h4><a name="bind_3">template<class R, class F, class A1> <i>unspecified-3</i> bind(F
	673	f, A1 a1)</a></h4>
	674	<blockquote>
	675	<p><b>Returns:</b> A function object <i>λ</i> such that the expression <tt>λ(v<sub>1</sub>,
	676	v<sub>2</sub>, ..., v<sub>m</sub>)</tt> is equivalent to <tt><b>f</b>(µ(<b>a1</b>,
	677	v<sub>1</sub>, v<sub>2</sub>, ..., v<sub>m</sub>))</tt>, implicitly
	678	converted to <b>R</b>.</p>
	679	<p><b>Throws:</b> Nothing unless the copy constructors of <b>F</b> or <b>A1</b> throw
	680	an exception.</p>
	681	</blockquote>
	682	<h4><a name="bind_3_1">template<class F, class A1> <i>unspecified-3-1</i> bind(F
	683	f, A1 a1)</a></h4>
	684	<blockquote>
	685	<p><b>Effects:</b> Equivalent to <tt>bind<typename F::result_type, F, A1>(f, a1);</tt></p>
	686	<p><b>Notes:</b> Implementations are allowed to infer the return type of <b>f</b> via
	687	other means as an extension, without relying on the <tt>result_type</tt> member.</p>
	688	</blockquote>
	689	<h4><a name="bind_4">template<class R, class B1, class A1> <i>unspecified-4</i> bind(R
	690	(*f) (B1), A1 a1)</a></h4>
	691	<blockquote>
	692	<p><b>Returns:</b> A function object <i>λ</i> such that the expression <tt>λ(v<sub>1</sub>,
	693	v<sub>2</sub>, ..., v<sub>m</sub>)</tt> is equivalent to <tt><b>f</b>(µ(<b>a1</b>,
	694	v<sub>1</sub>, v<sub>2</sub>, ..., v<sub>m</sub>))</tt>.</p>
	695	<p><b>Throws:</b> Nothing unless the copy constructor of <b>A1</b> throws an
	696	exception.</p>
	697	</blockquote>
	698	<h4><a name="bind_5">template<class R, class T, class A1> <i>unspecified-5</i> bind(R
	699	(T::*f) (), A1 a1)</a></h4>
	700	<blockquote>
	701	<p><b>Effects:</b> Equivalent to <tt>bind<R>(<A href="mem_fn.html">boost::mem_fn</A>(f),
	702	a1);</tt></p>
	703	</blockquote>
	704	<h4><a name="bind_6">template<class R, class T, class A1> <i>unspecified-6</i> bind(R
	705	(T::*f) () const, A1 a1)</a></h4>
	706	<blockquote>
	707	<p><b>Effects:</b> Equivalent to <tt>bind<R>(<A href="mem_fn.html">boost::mem_fn</A>(f),
	708	a1);</tt></p>
	709	</blockquote>
	710	<h4><a name="bind_6_1">template<class R, class T, class A1> <i>unspecified-6-1</i>
	711	bind(R T::*f, A1 a1)</a></h4>
	712	<blockquote>
	713	<p><b>Effects:</b> Equivalent to <tt>bind<R>(<A href="mem_fn.html">boost::mem_fn</A>(f),
	714	a1);</tt></p>
	715	</blockquote>
	716	<h4><a name="bind_7">template<class R, class F, class A1, class A2> <i>unspecified-7</i>
	717	bind(F f, A1 a1, A2 a2)</a></h4>
	718	<blockquote>
	719	<p><b>Returns:</b> A function object <i>λ</i> such that the expression <tt>λ(v<sub>1</sub>,
	720	v<sub>2</sub>, ..., v<sub>m</sub>)</tt> is equivalent to <tt><b>f</b>(µ(<b>a1</b>,
	721	v<sub>1</sub>, v<sub>2</sub>, ..., v<sub>m</sub>), µ(<b>a2</b>, v<sub>1</sub>,
	722	v<sub>2</sub>, ..., v<sub>m</sub>))</tt>, implicitly converted to <b>R</b>.</p>
	723	<p><b>Throws:</b> Nothing unless the copy constructors of <b>F</b>, <b>A1</b> or <b>A2</b>
	724	throw an exception.</p>
	725	</blockquote>
	726	<h4><a name="bind_7_1">template<class F, class A1, class A2> <i>unspecified-7-1</i>
	727	bind(F f, A1 a1, A2 a2)</a></h4>
	728	<blockquote>
	729	<p><b>Effects:</b> Equivalent to <tt>bind<typename F::result_type, F, A1, A2>(f,
	730	a1, a2);</tt></p>
	731	<p><b>Notes:</b> Implementations are allowed to infer the return type of <b>f</b> via
	732	other means as an extension, without relying on the <tt>result_type</tt> member.</p>
	733	</blockquote>
	734	<h4><a name="bind_8">template<class R, class B1, class B2, class A1, class A2> <i>unspecified-8</i>
	735	bind(R (*f) (B1, B2), A1 a1, A2 a2)</a></h4>
	736	<blockquote>
	737	<p><b>Returns:</b> A function object <i>λ</i> such that the expression <tt>λ(v<sub>1</sub>,
	738	v<sub>2</sub>, ..., v<sub>m</sub>)</tt> is equivalent to <tt><b>f</b>(µ(<b>a1</b>,
	739	v<sub>1</sub>, v<sub>2</sub>, ..., v<sub>m</sub>), µ(<b>a2</b>, v<sub>1</sub>,
	740	v<sub>2</sub>, ..., v<sub>m</sub>))</tt>.</p>
	741	<p><b>Throws:</b> Nothing unless the copy constructors of <b>A1</b> or <b>A2</b> throw
	742	an exception.</p>
	743	</blockquote>
	744	<h4><a name="bind_9">template<class R, class T, class B1, class A1, class A2> <i>unspecified-9</i>
	745	bind(R (T::*f) (B1), A1 a1, A2 a2)</a></h4>
	746	<blockquote>
	747	<p><b>Effects:</b> Equivalent to <tt>bind<R>(<A href="mem_fn.html">boost::mem_fn</A>(f),
	748	a1, a2);</tt></p>
	749	</blockquote>
	750	<h4><a name="bind_10">template<class R, class T, class B1, class A1, class A2> <i>unspecified-10</i>
	751	bind(R (T::*f) (B1) const, A1 a1, A2 a2)</a></h4>
	752	<blockquote>
	753	<p><b>Effects:</b> Equivalent to <tt>bind<R>(<A href="mem_fn.html">boost::mem_fn</A>(f),
	754	a1, a2);</tt></p>
	755	</blockquote>
	756	<h3><a name="AdditionalOverloads">Additional overloads</a></h3>
	757	<p>Implementations are allowed to provide additional <b>bind</b> overloads in order
	758	to support more arguments or different function pointer variations.</p>
	759	<h2><a name="Implementation">Implementation</a></h2>
	760	<h3><a name="Files">Files</a></h3>
	761	<ul>
	762	<li>
	763	<A href="../../boost/bind.hpp">boost/bind.hpp</A>
	764	(main header)
	765	<li>
	766	<A href="../../boost/bind/bind_cc.hpp">boost/bind/bind_cc.hpp</A>
	767	(used by bind.hpp, do not include directly)
	768	<li>
	769	<A href="../../boost/bind/bind_mf_cc.hpp">boost/bind/bind_mf_cc.hpp</A>
	770	(used by bind.hpp, do not include directly)
	771	<li>
	772	<A href="../../boost/bind/bind_template.hpp">boost/bind/bind_template.hpp</A>
	773	(used by bind.hpp, do not include directly)
	774	<LI>
	775	<A href="../../boost/bind/arg.hpp">boost/bind/arg.hpp</A>
	776	(defines the type of the placeholder arguments)
	777	<LI>
	778	<A href="../../boost/bind/placeholders.hpp">boost/bind/placeholders.hpp</A>
	779	(defines the _1, _2, ... _9 placeholders)
	780	<LI>
	781	<A href="../../boost/bind/apply.hpp">boost/bind/apply.hpp</A> (<STRONG>apply</STRONG>
	782	helper function object)
	783	<LI>
	784	<A href="../../boost/bind/protect.hpp">boost/bind/protect.hpp</A> (<STRONG>protect</STRONG>
	785	helper function)
	786	<LI>
	787	<A href="../../boost/bind/make_adaptable.hpp">boost/bind/make_adaptable.hpp</A>
	788	(<STRONG>make_adaptable</STRONG>
	789	helper function)
	790	<li>
	791	<A href="test/bind_test.cpp">libs/bind/test/bind_test.cpp</A>
	792	(test)
	793	<li>
	794	<A href="bind_as_compose.cpp">libs/bind/bind_as_compose.cpp</A>
	795	(function composition example)
	796	<li>
	797	<A href="bind_visitor.cpp">libs/bind/bind_visitor.cpp</A>
	798	(visitor example)
	799	<li>
	800	<A href="test/bind_stdcall_test.cpp">libs/bind/test/bind_stdcall_test.cpp</A>
	801	(test with __stdcall functions)
	802	<li>
	803	<A href="test/bind_stdcall_mf_test.cpp">libs/bind/test/bind_stdcall_mf_test.cpp</A>
	804	(test with __stdcall member functions)
	805	<li>
	806	<A href="test/bind_fastcall_test.cpp">libs/bind/test/bind_fastcall_test.cpp</A>
	807	(test with __fastcall functions)
	808	<li>
	809	<A href="test/bind_fastcall_mf_test.cpp">libs/bind/test/bind_fastcall_mf_test.cpp</A>
	810	(test with __fastcall member functions)</li></ul>
	811	<h3><a name="Dependencies">Dependencies</a></h3>
	812	<ul>
	813	<li>
	814	<A href="../config/config.htm">Boost.Config</A>
	815	<li>
	816	<A href="ref.html">boost/ref.hpp</A>
	817	<li>
	818	<A href="mem_fn.html">boost/mem_fn.hpp</A>
	819	<li>
	820	<A href="../../boost/type.hpp">boost/type.hpp</A></li>
	821	</ul>
	822	<h3><a name="NumberOfArguments">Number of Arguments</a></h3>
	823	<p>This implementation supports function objects with up to nine arguments. This is
	824	an implementation detail, not an inherent limitation of the design.</p>
	825	<h3><a name="stdcall">"__stdcall", "__cdecl", "__fastcall", and "pascal" Support</a></h3>
	826	<p>Some platforms allow several types of (member) functions that differ by their <b>calling
	827	convention</b> (the rules by which the function is invoked: how are
	828	arguments passed, how is the return value handled, and who cleans up the stack
	829	- if any.)</p>
	830	<p>For example, Windows API functions and COM interface member functions use a
	831	calling convention known as <b>__stdcall</b>.Borland VCL components use <STRONG>__fastcall</STRONG>.
	832	Mac toolbox functions use a <b>pascal</b> calling convention.</p>
	833	<p>To use <b>bind</b> with <b>__stdcall</b> functions, <b>#define</b> the macro <b>BOOST_BIND_ENABLE_STDCALL</b>
	834	before including <b><boost/bind.hpp></b>.</p>
	835	<p>To use <b>bind</b> with <b>__stdcall</b> <b>member</b> functions, <b>#define</b>
	836	the macro <b>BOOST_MEM_FN_ENABLE_STDCALL</b> before including <b><boost/bind.hpp></b>.</p>
	837	<P>To use <B>bind</B> with <B>__fastcall</B> functions, <B>#define</B> the macro <B>BOOST_BIND_ENABLE_FASTCALL</B>
	838	before including <B><boost/bind.hpp></B>.</P>
	839	<P>To use <B>bind</B> with <B>__fastcall</B> <B>member</B> functions, <B>#define</B>
	840	the macro <B>BOOST_MEM_FN_ENABLE_FASTCALL</B> before including <B><boost/bind.hpp></B>.</P>
	841	<P>To use <b>bind</b> with <b>pascal</b> functions, <b>#define</b> the macro <b>BOOST_BIND_ENABLE_PASCAL</b>
	842	before including <b><boost/bind.hpp></b>.</P>
	843	<P>To use <B>bind</B> with <B>__cdecl</B> <B>member</B> functions, <B>#define</B> the
	844	macro <B>BOOST_MEM_FN_ENABLE_CDECL</B> before including <B><boost/bind.hpp></B>.</P>
	845	<P><STRONG>It is best to define these macros in the project options, via -D on the
	846	command line, or as the first line in the translation unit (.cpp file) where
	847	bind is used.</STRONG> Not following this rule can lead to obscure errors
	848	when a header includes bind.hpp before the macro has been defined.</P>
	849	<p>[Note: this is a non-portable extension. It is not part of the interface.]</p>
	850	<p>[Note: Some compilers provide only minimal support for the <b>__stdcall</b> keyword.]</p>
	851	<h3><a name="visit_each"><b>visit_each</b> support</a></h3>
	852	<p>Function objects returned by <b>bind</b> support the experimental and
	853	undocumented, as of yet, <b>visit_each</b> enumeration interface.</p>
	854	<p>See <A href="bind_visitor.cpp">bind_visitor.cpp</A> for an example.</p>
	855	<h2><a name="Acknowledgements">Acknowledgements</a></h2>
	856	<p>Earlier efforts that have influenced the library design:</p>
	857	<ul>
	858	<li>
	859	The <a href="http://staff.cs.utu.fi/BL/">Binder Library</a>
	860	by Jaakko Järvi;
	861	<li>
	862	The <a href="../lambda/index.html">Lambda Library</a>
	863	(now part of Boost) by Jaakko Järvi and Gary Powell (the successor to the
	864	Binder Library);
	865	<li>
	866	<a href="http://more.sourceforge.net/">Extensions to the
	867	STL</a> by Petter Urkedal.</li></ul>
	868	<p>Doug Gregor suggested that a visitor mechanism would allow <b>bind</b> to
	869	interoperate with a signal/slot library.</p>
	870	<p>John Maddock fixed a MSVC-specific conflict between <b>bind</b> and the <A href="../type_traits/index.html">
	871	type traits library</A>.</p>
	872	<p>Numerous improvements were suggested during the formal review period by Ross
	873	Smith, Richard Crossley, Jens Maurer, Ed Brey, and others. Review manager was
	874	Darin Adler.
	875	</p>
	876	<p>The precise semantics of <b>bind</b> were refined in discussions with Jaakko
	877	Järvi.
	878	</p>
	879	<p>Dave Abrahams fixed a MSVC-specific conflict between <b>bind</b> and the <A href="../utility/iterator_adaptors.htm">
	880	iterator adaptors library</A>.
	881	</p>
	882	<p>Dave Abrahams modified <b>bind</b> and <b>mem_fn</b> to support void returns on
	883	deficient compilers.
	884	</p>
	885	<p>Mac Murrett contributed the "pascal" support enabled by
	886	BOOST_BIND_ENABLE_PASCAL.
	887	</p>
	888	<p>The alternative <tt>bind(type<R>(), f, ...)</tt> syntax was inspired by a
	889	discussion with Dave Abrahams and Joel de Guzman.</p>
	890	<p><br>
	891	<br>
	892	<br>
	893	<small>Copyright © 2001, 2002 by Peter Dimov and Multi Media Ltd. Copyright
	894	2003-2005 Peter Dimov. Permission to copy, use, modify, sell and distribute
	895	this document is granted provided this copyright notice appears in all copies.
	896	This document is provided "as is" without express or implied warranty, and with
	897	no claim as to its suitability for any purpose.</small></p>
	898	</body>
	899	</html>

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