The MPL Reference Manual: negate

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# negate

### Synopsis

    template<
          typename T
        >
    struct negate
    {
        typedef unspecified type;
    };

### Description

Returns the negative (additive inverse) of its argument.

### Header

    #include <boost/mpl/negate.hpp>
    #include <boost/mpl/arithmetic.hpp>

### Model of

Numeric Metafunction

### Parameters

Parameter | Requirement | Description
--- | --- | ---
`T` | Integral Constant | Operation's argument.

[Note: The requirements listed in this specification are the ones imposed by the default implementation. See Numeric Metafunction concept for the details on how to provide an implementation for a user-defined numeric type that does not satisfy the Integral Constant requirements. — end note]

### Expression semantics

For any Integral Constant `c`:

    typedef negate<c>::type r;

Return type: | Integral Constant.
Semantics: | Equivalent to
    typedef integral_c< c::value_type, ( -c::value ) > r;

    typedef negate<c> r;

Return type: | Integral Constant.
Semantics: | Equivalent to
    struct r : negate<c>::type {};

### Complexity

Amortized constant time.

### Example

    typedef negate< int_<-10> >::type r;
    BOOST_MPL_ASSERT_RELATION( r::value, ==, 10 );
    BOOST_MPL_ASSERT(( is_same< r::value_type, int > ));

### See also

Arithmetic Operations, Numeric Metafunction, numeric_cast, plus, minus, times