115 lines
2.0 KiB
ReStructuredText
115 lines
2.0 KiB
ReStructuredText
.. Metafunctions/Comparisons//equal_to |50
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equal_to
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========
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Synopsis
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--------
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.. parsed-literal::
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template<
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typename T1
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, typename T2
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>
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struct equal_to
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{
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typedef |unspecified| type;
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};
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Description
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-----------
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Returns a true-valued |Integral Constant| if ``T1`` and ``T2`` are equal.
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Header
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------
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.. parsed-literal::
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#include <boost/mpl/equal_to.hpp>
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#include <boost/mpl/comparison.hpp>
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Model of
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--------
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|Numeric Metafunction|
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Parameters
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----------
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+---------------+---------------------------+-----------------------------------------------+
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| Parameter | Requirement | Description |
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+===============+===========================+===============================================+
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| ``T1``, ``T2``| |Integral Constant| | Operation's arguments. |
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+---------------+---------------------------+-----------------------------------------------+
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|Note:| |numeric metafunction note| |-- end note|
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Expression semantics
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--------------------
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For any |Integral Constant|\ s ``c1`` and ``c2``:
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.. parsed-literal::
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typedef equal_to<c1,c2>::type r;
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:Return type:
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|Integral Constant|.
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:Semantics:
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Equivalent to
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.. parsed-literal::
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typedef bool_< (c1::value == c2::value) > r;
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.. ..........................................................................
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.. parsed-literal::
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typedef equal_to<c1,c2> r;
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:Return type:
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|Integral Constant|.
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:Semantics:
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Equivalent to
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.. parsed-literal::
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struct r : equal_to<c1,c2>::type {};
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Complexity
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----------
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Amortized constant time.
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Example
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-------
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.. parsed-literal::
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BOOST_MPL_ASSERT_NOT(( equal_to< int_<0>, int_<10> > ));
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BOOST_MPL_ASSERT_NOT(( equal_to< long_<10>, int_<0> > ));
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BOOST_MPL_ASSERT(( equal_to< long_<10>, int_<10> > ));
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See also
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--------
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|Comparisons|, |Numeric Metafunction|, |numeric_cast|, |not_equal_to|, |less|
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