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Doc patch; refs #4532

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[SVN r66973]
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Marshall Clow
2010-12-02 13:17:09 +00:00
parent f89c41dc7b
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@@ -61,6 +61,7 @@
bind&lt;R&gt;(f, ...)</A></h4>
<h4 style="MARGIN-LEFT: 40pt"><A href="#err_nonstd">Binding a nonstandard function</A></h4>
<h4 style="MARGIN-LEFT: 40pt"><A href="#err_overloaded">Binding an overloaded function</A></h4>
<h4 style="MARGIN-LEFT: 40pt"><A href="#err_modeling_stl_function_object_concepts">Modeling STL function object concepts</A></h4>
<h4 style="MARGIN-LEFT: 40pt"><A href="#err_const_arg"><b>const</b> in signatures</A></h4>
<h4 style="MARGIN-LEFT: 40pt"><A href="#err_msvc_using">MSVC specific: using
boost::bind;</A></h4>
@@ -585,6 +586,48 @@ int main()
boost::bind( get, _1 );
}
</pre>
<h3><a name="err_modeling_stl_function_object_concepts">Modeling STL function object concepts</a></h3>
<p>The function objects that are produced by <b>boost::bind</b> do not model the
STL <a href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary Function</a> or
<a href="http://www.sgi.com/tech/stl/BinaryFunction.html">Binary Function</a> concepts,
even when the function objects are unary or binary operations, because the function object
types are missing public typedefs <tt>result_type</tt> and <tt>argument_type</tt> or
<tt>first_argument_type</tt> and <tt>second_argument_type</tt>. In cases where these
typedefs are desirable, however, the utility function <tt>make_adaptable</tt>
can be used to adapt unary and binary function objects to these concepts. This allows
unary and binary function objects resulting from <b>boost::bind</b> to be combined with
STL templates such as <a href="http://msdn.microsoft.com/en-us/library/se0409db%28v=VS.90%29.aspx"><tt>std::unary_negate</tt></a>
and <a href="http://msdn.microsoft.com/en-us/library/833073z4%28v=VS.90%29.aspx"><tt>std::binary_negate</tt></a>.</p>
<p>The <tt>make_adaptable</tt> function is defined in &lt;<a href="../../boost/bind/make_adaptable.hpp">boost/bind/make_adaptable.hpp</a>&gt;,
which must be included explicitly in addition to &lt;boost/bind.hpp&gt;:</p>
<pre>
#include &lt;boost/bind/make_adaptable.hpp&gt;
template &lt;class R, class F&gt; <i>unspecified-type</i> make_adaptable(F f);
template&lt;class R, class A1, class F&gt; <i>unspecified-unary-functional-type</i> make_adaptable(F f);
template&lt;class R, class A1, class A2, class F&gt; <i>unspecified-binary-functional-type</i> make_adaptable(F f);
template&lt;class R, class A1, class A2, class A3, class F&gt; <i>unspecified-ternary-functional-type</i> make_adaptable(F f);
template&lt;class R, class A1, class A2, class A3, class A4, class F&gt; <i>unspecified-4-ary-functional-type</i> make_adaptable(F f);
</pre>
<p>This example shows how to use <tt>make_adaptable</tt> to make a predicate for "is not a space":</p>
<pre>typedef char char_t;
std::locale loc("");
const std::ctype&lt;char_t&gt;&amp; ct = std::use_facet&lt;std::ctype&lt;char_t&gt; &gt;(loc);
auto isntspace = std::not1( boost::make_adaptable&lt;bool, char_t&gt;( boost::bind(&amp;std::ctype&lt;char_t&gt;::is, &amp;ct, std::ctype_base::space, _1) ) );
</pre>
<p>In this example, <b>boost::bind</b> creates the "is a space" (unary) predicate.
It is then passed to <tt>make_adaptable</tt> so that a function object modeling
the Unary Function concept can be created, serving as the argument to
<a href="http://msdn.microsoft.com/en-us/library/syyszzf8%28v=VS.90%29.aspx"><tt>std::not1</tt></a>.</p>
<h3><a name="err_const_arg"><b>const</b> in signatures</a></h3>
<p>Some compilers, including MSVC 6.0 and Borland C++ 5.5.1, have problems with the
top-level <b>const</b> in function signatures: