Nathan Ridge a écrit :
Hello,
I'm wondering if there is a way to force boost::function to only accept functions/functors with the exact same signature.
I need this because there are cases in my program where passing a function with a different but convertible signature is almost certainly an error, and it would really be nice if such uses triggered a compiler error.
For instance, boost::function will readily convert a mutator function with this signature:
boost::function doesn't really "convert" anything. The boost::function<sig> objects simply define an operator() with the `sig' signature, which in turns calls the wrapped function object by means of a virtual function call. So if your function is callable from a `sig' context, it works even though that's not its exact signature, because the arguments specified are convertible to the real arguments and the real return type is convertible to the specified return type. It doesn't really make sense to worry about the exact signature in my opinion; Anyway, if you want to test the signature of a function object, just take the address of &T::operator() and check it is what you want. Of course that won't work if it's a template or if it is overloaded.