std::function::target
From cppreference.com
< cpp | utility | functional | function
| template< class T > T* target(); |
(1) | (since C++11) |
| template< class T > const T* target() const; |
(2) | (since C++11) |
Returns a pointer to the stored callable function target.
Parameters
(none)
Return value
A pointer to the stored function if target_type() == typeid(T), otherwise a null pointer.
Exceptions
noexcept specification:
noexcept
Example
Run this code
#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
See also
| obtains the typeid of the stored target (public member function) |