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');

```
I know I'll get downvoted for this, but I honestly think this is one case where the preprocessor can usefully be used:

```
#define CHECK( fn ) \
    { \
        if( fn > 0 ) { \
            throw "problem"; \
        } \
    } 

int f(int x) {
    return x - 1;
}

int main() {
    CHECK( f(42) );
}

```

It's clear, it's short, it's simple, and it could be made to make use of the `__LINE__`, `__FILE__` and other pre-defined macros, which you can't do with templates.