How to pass a member function as pthread start_routine?

How to pass a member function as pthread start_routine?

I got that:
void* xxx::yyy(void* ThreadIdPtr)
And now I do that:
pthread_create( &tp, NULL, xxx::yyy, (void*) &i);
but compile error:
error: argument of type 'void* (xxx::)(void*)' does not match
'void* (*)(void*)'
How to pass it correctly?