Create template function for function that accepts function pointers as parameters for many types of functions

Question

I have several c functions that do pretty much the exact same thing except for functions on one line. I want to replace all of these functions with one function that I can pass as function pointer for that one line:

Func1(type parameter);

Func2(type1 parameter1,type2 parameter2);

FuncFunc(FunctionPointer functionPointer){
    funcVar;
    ...
    functionPointer(funcVar,....);
    ...
}

int main(){
    FuncFunc(Func1);

    FuncFunc(Func2(,type2Object));
}

Is there anyway I can do this in C++?

Answer 1

It's not clear what you are trying to achieve, but here is an example how your code may me translated into valid C++. First, let's define your Func with maximum number of arguments:

template<typename T1, typename T2>
void Func(T1 par1, T2 par2) {
        std::cout << par1 << " " << par2 << std::endl;
}

Then we should make FuncFunc accept any function you want:

template<typename ...T>
void FuncFunc(const std::function<void(T...)>& fPtr) {
        std::string funcVar = "Foo!";
        fPtr(funcVar);
}

or easier to use variant:

template<typename F>
void GuncFunc(const F& fPtr) {
        std::string funcVar = "Foo!";
        fPtr(funcVar);
}

and finally use FuncFunc:

auto Func1 = std::bind(Func<float, std::string>, 3.14f, std::placeholders::_1);
auto Func2 = std::bind(Func<std::string, int>, std::placeholders::_1, 42);
FuncFunc(std::function<void(std::string)>(Func1));
FuncFunc(std::function<void(std::string)>(Func2));
return 0;

or GuncFunc:

// Using std::bind
GuncFunc(std::bind(Func<float, std::string>, 3.14f, std::placeholders::_1));
GuncFunc(std::bind(Func<std::string, int>, std::placeholders::_1, 42));

// Or using lambdas:
GuncFunc([](std::string s){Func<float, std::string>(3.14f, s);});
GuncFunc([](std::string s){Func<std::string, int>(s, 42);});

Choosing std::bind or lambdas seems to be out of scope of your question, but you may found something useful here, there or in this question.

Anyway, very likely you will need lambdas, std::function, std::bind or variadic templates.