Question: I use a (C) library with functions taking different parameters but always returning an int greater than zero in case of error:

```
int functionA(int param1, char param2); /* return an error code on failure, 0 otherwise */
int functionB(LIB_BOOLEAN param1);      /* return an error code on failure, 0 otherwise */
// ...

```

I would like to turn them all to be exception ready:

```
if (functionA(param1, param2) > 0)
{ throw std::runtime_error("Method failed"); }

```

Is it possible to write a template to do it once for all method ?

EDIT:
The idea is to avoid checking the result for each functions every time I use them.

Answer: 
Do you mean something like this?

```
template<typename F, typename... Args>
auto my_invoke(F &&f, Args&&... args) {
    if(std::forward<F>(f)(std::forward<Args>(args)...)) {
        throw std::runtime_error("Method failed");
    }
}

```

You can call it as;

```
my_invoke(functionA, 0, 'c');

```
Here is a template-based solution using C++17's new `auto` template parameters:

```
template <auto &> struct CallerImpl;

template <typename ...Args, int (&F)(Args ...)>
struct CallerImpl<F>
{
    static int CallOrThrow(Args ... args)
    {
        if (int n = F(args...); n > 0)
            throw std::runtime_error("Method failed");
        else
            return n;
    }
};

template <auto & F, typename ... Brgs>
int CallOrThrow(Brgs ... brgs)
{
    return CallerImpl<F>::CallOrThrow(brgs...);
}

```

Usage example:

```
int foo(double, char)
{
    std::cout << "Foo called\n";
    return 8;
}

CallOrThrow<foo>(1.5, 'x');

```