pointer to member function question.

#include

class test
{
public:

void logforown(const char *, ...);

typedef void (test::*func)(const char *, ...);

func useit();
};

void test::logforown(const char *, ...)
{
printf("test");
}

test::func test::useit()
{
return &test::logforown;
}

main()
{

test ins;

// below code, how can i fix it?
// (ins.useit())->*("i have question ='%d'", 10);
// (ins.useit()).*("i have question ='%d'", 10);

}