Error regarding 3rd parameter of pthread_create()

Could someone please explain to me the return type of pthread_create()'s 3rd parameter? I know it should be a function but I keep getting the error: argument of type 'void' (Test::)(void*)' does not match 'void * (*) (void*)'.

Here is the function that I pass to pthread_create():
And this is how I call pthread_create():

re: Error regarding 3rd parameter of pthread_create()

Test::run has to be a static function to avoid the compiler supplying the this pointer in as the first argument.