Question

Well, I’m gonna be pretty straightforward here, I just have a piece of code in c++ which I’m not sure I really understand and need some help with.

Ok, to simplify lets just say I have a class that is defined like this: (the real class is a little bit more complicated, but this is what matters)

class myClass : public Runnable {
    Semaphore *m_pMySemaphore;
    __Queue<Requests> *m_pQueue;
    Request m_Request;
    VetorSlotBuffer *m_vetorSlotBuffer;
}

Up to here nothing is wrong, myClass is just a regular class which has 3 members that actually are pointers to other classes and an object of the class Request, the implementation of those classes not being important for my point here.

Then when this person implemented the constructor for myClass he or she did this:

myClass::myClass() : m_pMySemaphore(0), m_pQueue(0), m_vetorSlotBuffer(0) {
}

It’s pretty evident that those three variables are treated like that by the constructor because they are pointers, am I right? but what kind of syntax is that? am I setting the pointers to null by doing that? I’ve seen a little bit of c++ already but never found something like that.

And secondly, what’s the deal with the “:” after the constructor declaration? that I’ve seen but never took the time to investigate. Is this like an inner class or something?

Thank you very much in advance.
Nelson R. Perez

Answer 1

This is an initialization list

And it’s the recommended way to initialize your members