pre::type_traits::function_traits< F, typename > Struct Template Reference

Provides access to lambda and functions arity, return type, arguments type and access as std::function type: More...

Detailed Description

template<typename F, typename = void>
struct pre::type_traits::function_traits< F, typename >

Provides access to lambda and functions arity, return type, arguments type and access as std::function type:

Parameters

F	The function, function pointer or lambda type to introspect, pass it as decltype(your_lambda).

#include <iostream>
#include <typeinfo>
#include <pre/traits/function_traits.hpp>
#include <pre/functional/to_std_function.hpp>

int main() {

    auto my_lambda = [](bool arg_0, int arg_1, double arg_2, std::string arg_3) {
                            return int{0} ;
                        };

    typedef pre::type_traits::function_traits<decltype(my_lambda)> my_lambda_types;

    std::cout << "my_lambda number of arguments " << my_lambda_types::arity                        << std::endl;
    std::cout << "my_lambda return type is "      << typeid(my_lambda_types::result_type).name()   << std::endl;
    std::cout << "my_lambda argument 0 type is "  << typeid(my_lambda_types::arg<0>).name()        << std::endl;
    std::cout << "my_lambda argument 1 type is "  << typeid(my_lambda_types::arg<1>).name()        << std::endl;
    std::cout << "my_lambda argument 2 type is "  << typeid(my_lambda_types::arg<2>).name()        << std::endl;
    std::cout << "my_lambda argument 3 type is "  << typeid(my_lambda_types::arg<3>).name()        << std::endl;
    std::cout << "my_lambda function type is "    << typeid(my_lambda_types::function_type).name() << std::endl;

    auto std_function = pre::functional::to_std_function(my_lambda);

    std::cout << "my_lambda called as std::function "  << std_function(true, int{42}, double{3.14}, std::string{"Hello World"}) << std::endl;

    return 0;
}

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

• pre/type_traits/function_traits.hpp