How to define function that takes the most generic number and types of parameters

Question

How can I redefine this function:

unsigned int uiTimer(int milliseconds, int (*f)(void *data), void *data)

so that it can take this function as a param (or any other function regardless of signature) ?

int filterInput(uiEditableCombobox *pBox, void *pvData)

like this:

uiTimer(1000, filterInput, NULL);

I tried wrapping filterInput in a "timerDone(void *)" but this cannot be done because I need to pass the parameters into filterInput.

int timerDone(void *) {
    filterInput();  // <--- I need context to be passed as params
}
uiTimer(1000, timerDone, NULL);

Answer 1

Change signature to use std::function :

#include <functional>
unsigned int uiTimer(int milliseconds, std::function<int(void*)> f, void *data)

Pass parameters using lambda expressions :

uiEditableCombobox *box;
uiTimer(1000, [=](void* data) { return filterInput(box, data); }, nullptr);

Answer 2

You can take any function pointer as argument this way:

template<typename R, typename... Ts>
void f(R(*functionPointer)(Ts...))
{ /* ... */ }

Unfortunately, separate case is necessary for member function pointers:

template<typename R, typename T, typename... Ts>
void f(R(T::*functionPointer)(Ts...))
{ /* ... */ }

But in essence, any function pointer will be also caught by single template parameter since it's also a valid type, but then you must be aware that you are allowing much more entities to be passed (eg not a function pointers).

template<typename T>
void f(T&& f)
{ /* ... */ }

Here is a working example that shows mutiple ways of using function pointers in template functions: http://coliru.stacked-crooked.com/a/a1a01993266e6351