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clinkage

Block scope and internal linkage?

From the C18 standard (6.7.9):

If the declaration of an identifier has block scope, and the identifier has external or internal linkage, the declaration shall have no initializer for the identifier.

I have no problem with block scope + external linkage. But, I can't see how can an identifier have block scope and internal linkage. Is that even possible?

Solution

  • If your global is defined

    static int hui;

    it has internal linkage. Then

    void f(void) {
    extern int hui;

}

    refers to the same object with internal linkage, even if the keyword says extern.

    So extern is a misnomer and should probably be linkage or so.