Question

Basically, I would like to be able to be able to pass a function_A with any parameter to T_function, so that T_function could execute some commands, then call the passed-in function

This is what I came up with (which might make my goal more clear) :

template <typename t_return, typename t_param>
void foo(t_return (*func)(t_param), t_param p)
{
    //do code
    func(p);
}

foo<void, int>(&someFunc, someInt);

The above code works great, but it seems bothersome. I’m also not sure how fool-proof it is. Does anyone with a little more understanding have an improvement?
I’ve tried looking this up online, however it has proved difficult to search for.

Answer 1

You could just make the whole function type a template parameter. Then the compiler can deduce the template parameters using the input arguments.

template <typename F, typename T>
void foo (F func, const T& p)
{
    // do code
    func(p);
}

foo(&someFunc, someInt);

This also has an advantage that function objects can be supported. (This is also how the standard library (“STL”) supports passing functions to the algorithms.)