Thread: What is function(void *arg)

Originally Posted by Elysia

This can be avoided with template, as shown below:

The method you and Laserlight are talking about is definitely a good one, but it still, in theory, allows the possibility for the callback driver to poke around inside the T object when it shouldn't. In practice, this would be extremely difficult because you don't know what's in there, but a void * completely guarantees that the code won't touch it, since it has no idea what type it is (even as a template parameter).

Normally though, I'd define a callback API like this:

Code:

class Callback
{
public:
    virtual ~Callback() {}

    virtual void DoIt() = 0;
};

void DriveTheCallback(Callback *cb)
{
    cb->DoIt();
}

The actual callback just inherits from Callback and overrides DoIt().