static variable declaration and definition in C++

Question

I have a sample code as shown below:

 class myclass
{
public:
    static int j;
    myclass(){};
    ~myclass(){};
};

int main(int argc, char** argv) {
    myclass obj;
    return EXIT_SUCCESS;
}

Now I have declared a static int inside myclass and although I have not defined it, the compiler does not give me any errors until I began using the static variable. Why is that?

You only need a definition if you odr-use it.

T.C.
– T.C.

2014-10-07 17:03:15 +00:00
Commented Oct 7, 2014 at 17:03 — T.C.
– T.C., Commented Oct 7, 2014 at 17:03

dom0 · Accepted Answer · 2014-10-07 17:01:53Z

2

Because these are linker errors, not compiler errors. Linker errors never arise until you use an undefined symbol.

answered Oct 7, 2014 at 17:01

dom0

7,5063 gold badges32 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

πάντα ῥεῖ · Accepted Answer · 2014-10-07 17:02:06Z

2

"the compiler does not give me any errors until I began using the static variable. Why is that?"

Because it didn't need to be linked with your code until that point (when you start to use it). Unused code is ignored / stripped off by the linker.

answered Oct 7, 2014 at 17:02

πάντα ῥεῖ

88.9k13 gold badges125 silver badges199 bronze badges

1 Comment

dom0 Over a year ago

This issue has nothing to do with the linker discarding unused symbols' definitions.

Collectives™ on Stack Overflow

static variable declaration and definition in C++

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related