function_ref< Signature > Class Template Reference

A non-owning view of an object callable with a function signature.A function_ref is a non-owning view to a callable object or function pointer for a given signature. More...

Detailed Description

template<typename Signature>
class cxxomfort::impl::p0792::function_ref< Signature >

A non-owning view of an object callable with a function signature.

A function_ref is a non-owning view to a callable object or function pointer for a given signature.

Basically it's the equivalent to what array_ref is for contiguous sequences or what reference_wrapper and any are to normal types.

// note here we don't require a template for the functor
template <typename List>
vector<int> metafunction (function_ref<int(float)> F, List& L) {
    vector<int> sideeffects;
    for (typename L::reference ll : L) {
        sideeffects.push_back ( F(ll) );
    }
    return sideeffects;
}

int foo (float x) { ... };
int bar (float r) { ... };


list<float> data = ...;
vector<int> allfoos = metafunction(foo, data);
vector<int> allbars = metafunction(bar, data);

function_ref is a _ref - hence it does not work with temporaries such as bind expressions. The following doesn't work:

metafunction ( bind(mem_fn(&string::size), foo ) );

Note

In C++03 mode, function_ref can only construct from function pointers explicitly.

See also

• WG21 index 0792r0 function_ref proposal
• functional/function @ cppreference

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

• p0792-function_ref.hpp