cds::opt::equal_to< Functor > Struct Template Reference

[type-option] Option setter for opt::equal_to predicate More...

#include <cds/opt/compare.h>

Detailed Description

template<typename Functor>
struct cds::opt::equal_to< Functor >

[type-option] Option setter for opt::equal_to predicate

The option sets a binary predicate that tests whether a value of a specified type is equal to another value of that type. Functor interface is similar to std::equal_to predicate interface. The standard predicate std::equal_to can act as Functor:

typedef cds::opt::equal_to< std::equal_to< int > > opt_equal_to 

In addition, the option setter may sets non-standard 2-type (or even N-type) predicate (std::binary_function):

struct foo {
    int n;
};

template <typename T, typename Q>
struct pred_equal_to {
    bool operator ()( const T& t, const Q& q )
    { return t.n == q ; }
    bool operator ()( const Q& q, const T& t )
    { return q == t.n ; }
    bool operator ()( const T& t1, const T& t2 )
    { return t1.n == t2.n ; }
    bool operator ()( const Q& q1, const Q& q2 )
    { return q1 == q2 ; }
};

typedef cds::opt::equal_to< pred_equal_to< foo, int > > opt_equal_to;

Generally, the default type for Functor is std::equal_to but it depends on the container used.

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The documentation for this struct was generated from the following file:

• cds/opt/compare.h