template< class T > T* target() noexcept; | (1) | (since C++11) |
template< class T > const T* target() const noexcept; | (2) | (since C++11) |
Returns a pointer to the stored callable function target.
(none).
A pointer to the stored function if target_type() == typeid(T)
, otherwise a null pointer.
#include <functional> #include <iostream> int f(int, int) { return 1; } int g(int, int) { return 2; } void test(std::function<int(int, int)> const& arg) { std::cout << "test function: "; if (arg.target<std::plus<int>>()) std::cout << "it is plus\n"; if (arg.target<std::minus<int>>()) std::cout << "it is minus\n"; int (*const* ptr)(int, int) = arg.target<int(*)(int, int)>(); if (ptr && *ptr == f) std::cout << "it is the function f\n"; if (ptr && *ptr == g) std::cout << "it is the function g\n"; } int main() { test(std::function<int(int, int)>(std::plus<int>())); test(std::function<int(int, int)>(std::minus<int>())); test(std::function<int(int, int)>(f)); test(std::function<int(int, int)>(g)); }
Output:
test function: it is plus test function: it is minus test function: it is the function f test function: it is the function g
obtains the typeid of the stored target (public member function) |
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