invoke

Description

Calls a Deferred Callable Object with the arguments from a Sequence.

The corresponding metafunction, result_of::invoke does not define a type member for target functions of non-class type whose arity is not satisfied by the size of the sequence.

The first template parameter can be specialized explicitly to avoid copying and/or to control the const qualification of a function object.

If the target function is a pointer to a class members, the corresponding object can be specified as a reference, pointer, or smart pointer. In case of the latter, a freestanding get_pointer function must be defined (Boost provides this function for std::auto_ptr and boost::shared_ptr).

Synopsis

template<
    typename Function, 
    class Sequence
    >
typename result_of::invoke<Function, Sequence>::type
invoke(Function f, Sequence & s);

template<
    typename Function, 
    class Sequence
    >
typename result_of::invoke<Function, Sequence const>::type 
invoke(Function f, Sequence const & s);

Parameters

Parameter	Requirement	Description
`f`	A Deferred Callable Object	The function to call.
`s`	A Forward Sequence	The arguments.

Expression Semantics

invoke(f,s);

Return type: Return type of f when invoked with the elements in s as its arguments.

Semantics: Invokes f with the elements in s as arguments and returns the result of the call expression.

Header

#include <boost/fusion/functional/invocation/invoke.hpp>

Example

std::plus<int> add;
assert(invoke(add,make_vector(1,1)) == 2);