Need some clarification with a static class with static data members?
Hello.
To start off I have a header file with a class that holds static data and static data members. Something like this:
class ImAClass
{
private:
static std::vector<A*> listOfA_;
public:
ImAClass(void); //non-default constructor
static std::vector<A*>* GetListOfA(void) { return &listOfA_; }
};
And another class that holds a static version of this class:
class IHoldThings
{
public:
static ImAClass noReallyImAClass_;
};
Why is it that I get no errors when I define this outside of both classes?:
std::vector<A*> ImAClass::listOfA_; //seemingly does nothing? maybe??
But I get an unresolved external symbol error when I omit it?
Does listOfA_ exist before the compiler sees this call? If that is true, should I also construct the static class in IHoldThings in the same fashion, or is ImAClass's constructor enough for this purpose? Thanks in advance.
Re: Need some clarification with a static class with static data members?
Quote:
Originally Posted by Akira__tyler
Why is it that I get no errors when I define this outside of both classes?:
std::vector<A*> ImAClass::listOfA_; //seemingly does nothing? maybe??
Because you are correctly defining the static member variable (assuming that you do so in exactly one source file(.
Quote:
Originally Posted by Akira__tyler
But I get an unresolved external symbol error when I omit it?
Because without it, you only declared the static member variable, but never defined it.
By the way, contrary to the comment, this line declares a default constructor:
Code:
ImAClass(void); //non-default constructor
Remember to post your code in [code][/code] bbcode tags.
