I am returning to C++ after a long absence and I am stumbling a little over my understanding of the fairly well known static initialization problem.
Let's say I have a simple class Vector2 as given below (note that I am aware that x and y should be private with getters and setters, these have just been omitted for brevity):
class Vector2 {
public:
Vector2(float x, float y) :x(x), y(y) {};
float x,y;
}
Now, if I want to specify a static const member to represent a Vector2 with x and y set to 1, I am unsure on how to proceed - will static const members fall foul of the static initialization problem or will the act of making them const mean they are ok? I am toying with the following possibilities:
Possibility 1:
// .h
class Vector2 {
public:
Vector2(float x, float y) :x(x), y(y) {}
static const Vector2 ONE;
float x,y;
};
// .cpp
const Vector2 Vector2::ONE = Vector2(1.f, 1.f);
Possibility 2:
// .h
class Vector2 {
public:
Vector2(float x, float y) :x(x), y(y) {}
static const Vector2& getOne();
float x,y;
private:
static const Vector2 ONE;
};
// .cpp
const Vector2 Vector2::ONE = Vector2(1.f, 1.f);
static const Vector2& Vector2::getOne() {
return ONE;
}
Possibility 3:
// .h
class Vector2 {
public:
Vector2(float x, float y) :x(x), y(y) {}
static const Vector2& getOne();
float x,y;
};
// .cpp
const Vector2& Vector2::getOne() {
static Vector2 one(1.f,1.f);
return one;
}
Now, my preferred way to write this would be as in possibility 2, just because it is a more comfortable syntax for me. However, if I call the getOne() method from another static method in another class am I going to risk crashing and burning? As I say, it is because I am using a static const rather than a plain static that I am asking this question as I have found much on plain static class member issues, but nothing on const static issues.
I suspect that I gain nothing by the fact that I am using static const and will need to go with Possibility 3 to be safe, but I just want to ask in case someone can shed some light on this for me.
I realise I am probably opening myself up to a slew of links pointing to exactly what I am asking, but I have looked and not found before posting this.
Any help will be gratefully appreciated.
