C++11 thread from an existent class [duplicate]

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• Start thread with member function 3 answers

I'm certain that this is a simple design error, but I'm not sure where to go with it anyway.

I'd like to spawn a thread from an instance of a class. Specifically:

class Foo
{
    public:
        void bar() { /*do stuff*/ }
};

Usage:

int main()
{
    Foo foo_instance();

    std::thread foo_thread(foo_instance.bar);

    foo_thread.join();

    return 0;
}

When I compile the more detailed version of this, I get invalid use of non-static member function referring to the line std::thread foo_thread(foo_instance.bar);.

So, what am I misunderstanding here? I'd like the object to be initialized and "functional" before I spin it off into a thread, but clearly I'm not using the tools correctly.