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Question

为什么void();这里不会导致编译错误？

编译器如何根据标准对其进行解释？

class X;

int main()
{
    //void(int);    error: expected primary-expression before 'void'
    //void(void);   error: expected primary-expression before 'void'
    //void;         error: declaration does not declare anything [-fpermissive]
    //X();          error: invalid use of incomplete type 'class X'
    void(0);    // functional cast expression to void?
    void();     // ???
}