Is there a way to get class object in static function other than passing it as parameter?

Is there a way to get the class object in a class static function other than passing it as function argument? I cannot pass it as argument or make my class singleton.

class test{
public:
    int i=10;
    test(){}
    Static test_static_method(){
        // somehow get an object of the class to call class member.
        std::cout << classObj->i << "\n";
    }
};

I am trying to pass the static function to a C-API that takes in void(*)(). But I need class instance in my function to access the class data. Any help is appreciated.