forked from boostorg/bind
Data member support added.
[SVN r14640]
This commit is contained in:
Peter Dimov
54
mem_fn.html
54
mem_fn.html
@@ -45,7 +45,9 @@
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<b>boost::mem_fn</b> is a generalization of the standard functions <b>std::mem_fun</b>
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and <b>std::mem_fun_ref</b>. It supports member function pointers with more
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than one argument, and the returned function object can take a pointer, a
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reference, or a smart pointer to an object instance as its first argument.
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reference, or a smart pointer to an object instance as its first argument. <STRONG>mem_fn</STRONG>
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also supports pointers to data members by treating them as functions taking no
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arguments and returning a (const) reference to the member.
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</p>
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<p>
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The purpose of <b>mem_fn</b> is twofold. First, it allows users to invoke a
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@@ -87,8 +89,8 @@ template<class It, class R, class T> void for_each(It first, It last, R (T
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documentation of <b>bind</b></a> for an example.
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</p>
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<p>
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<b>mem_fn</b> takes one argument, a pointer to a member function, and returns a
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function object suitable for use with standard or user-defined algorithms:
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<b>mem_fn</b> takes one argument, a pointer to a member, and returns a function
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object suitable for use with standard or user-defined algorithms:
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</p>
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<pre>
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struct X
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@@ -136,7 +138,8 @@ void k(std::vector<boost::shared_ptr<X> > const & v)
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</p>
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<p>
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All function objects returned by <b>mem_fn</b> expose a <b>result_type</b> typedef
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that represents the return type of the member function.
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that represents the return type of the member function. For data members, <STRONG>result_type</STRONG>
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is defined as a const reference to the type of the member.
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</p>
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<h2><a name="FAQ">Frequently Asked Questions</a></h2>
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<h3><a name="Q1">Can <b>mem_fn</b> be used instead of the standard <b>std::mem_fun[_ref]</b>
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@@ -176,12 +179,14 @@ void k(std::vector<boost::shared_ptr<X> > const & v)
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namespace boost
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{
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template<class T> T * <a href="#get_pointer_1">get_pointer</a> (T * p);
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template<class T> T * <a href="#get_pointer_1">get_pointer</a>(T * p);
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template<class R, class T> <i>unspecified-1</i> <a href="#mem_fn_1">mem_fn</a>(R (T::*pmf) ());
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template<class R, class T> <i>unspecified-2</i> <a href="#mem_fn_2">mem_fn</a>(R (T::*pmf) () const);
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template<class R, class T> <i>unspecified-2-1</i> <a href="#mem_fn_2_1">mem_fn</a>(R T::*pm);
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template<class R, class T, class A1> <i>unspecified-3</i> <a href="#mem_fn_3">mem_fn</a>(R (T::*pmf) (A1));
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template<class R, class T, class A1> <i>unspecified-4</i> <a href="#mem_fn_4">mem_fn</a>(R (T::*pmf) (A1) const);
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@@ -196,11 +201,12 @@ template<class R, class T, class A1, class A2> <i>unspecified-6</i> <a hre
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</pre>
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<h3><a name="CommonRequirements">Common requirements</a></h3>
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<p>
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All <tt><i>unspecified-N</i></tt> types mentioned in the Synopsis
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are <b>CopyConstructible</b> and <b>Assignable</b>. Their copy constructors and
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assignment operators do not throw exceptions. <tt><i>unspecified-N</i>::result_type</tt>
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is defined as the return type of the member function pointer passed as an
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argument to <b>mem_fn</b> (<b>R</b> in the Synopsis.)
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All <tt><i>unspecified-N</i></tt> types mentioned in the Synopsis are <b>CopyConstructible</b>
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and <b>Assignable</b>. Their copy constructors and assignment operators do not
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throw exceptions. <tt><i>unspecified-N</i>::result_type</tt> is defined as the
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return type of the member function pointer passed as an argument to <b>mem_fn</b>
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(<b>R</b> in the Synopsis.) <tt><i>unspecified-2-1</i>::result_type</tt> is
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defined as <tt>R const &</tt>.
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</p>
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<h3><a name="get_pointer">get_pointer</a></h3>
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<h4><a name="get_pointer_1">template<class T> T * get_pointer(T * p)</a></h4>
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@@ -213,8 +219,8 @@ template<class R, class T, class A1, class A2> <i>unspecified-6</i> <a hre
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</p>
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</blockquote>
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<h3><a name="mem_fn">mem_fn</a></h3>
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<h4><a name="mem_fn_1">template<class R, class T> <i>unspecified-1</i>
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mem_fn(R (T::*pmf) ())</a></h4>
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<h4><a name="mem_fn_1">template<class R, class T> <i>unspecified-1</i> mem_fn(R
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(T::*pmf) ())</a></h4>
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<blockquote>
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<p>
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<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t)</i></tt>
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@@ -225,8 +231,8 @@ template<class R, class T, class A1, class A2> <i>unspecified-6</i> <a hre
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<b>Throws:</b> Nothing.
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</p>
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</blockquote>
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<h4><a name="mem_fn_2">template<class R, class T> <i>unspecified-2</i>
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mem_fn(R (T::*pmf) () const)</a></h4>
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<h4><a name="mem_fn_2">template<class R, class T> <i>unspecified-2</i> mem_fn(R
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(T::*pmf) () const)</a></h4>
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<blockquote>
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<p>
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<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t)</i></tt>
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@@ -238,8 +244,20 @@ template<class R, class T, class A1, class A2> <i>unspecified-6</i> <a hre
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<b>Throws:</b> Nothing.
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</p>
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</blockquote>
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<h4><a name="mem_fn_3">template<class R, class T, class A1> <i>unspecified-3</i>
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mem_fn(R (T::*pmf) (A1))</a></h4>
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<h4><a name="mem_fn_2_1">template<class R, class T> <i>unspecified-2-1</i> mem_fn(R
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T::*pm)</a></h4>
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<blockquote>
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<p>
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<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t)</i></tt>
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is equivalent to <tt>t.*pm</tt> when <i>t</i> is of type <STRONG>T</STRONG> <EM>[const]<STRONG>
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</STRONG></EM>or derived, <tt>get_pointer(t)->*pm</tt> otherwise.
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</p>
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<p>
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<b>Throws:</b> Nothing.
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</p>
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</blockquote>
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<h4><a name="mem_fn_3">template<class R, class T, class A1> <i>unspecified-3</i> mem_fn(R
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(T::*pmf) (A1))</a></h4>
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<blockquote>
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<p>
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<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t, a1)</i></tt>
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@@ -250,8 +268,8 @@ template<class R, class T, class A1, class A2> <i>unspecified-6</i> <a hre
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<b>Throws:</b> Nothing.
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</p>
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</blockquote>
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<h4><a name="mem_fn_4">template<class R, class T, class A1> <i>unspecified-4</i>
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mem_fn(R (T::*pmf) (A1) const)</a></h4>
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<h4><a name="mem_fn_4">template<class R, class T, class A1> <i>unspecified-4</i> mem_fn(R
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(T::*pmf) (A1) const)</a></h4>
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<blockquote>
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<p>
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<b>Returns:</b> a function object <i>f</i> such that the expression <tt><i>f(t, a1)</i></tt>
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