As far as I know, the
-mm -fs -fh -fw flags do not work with OS X because they require X11 to work. I've tried them in Linux and they work fine there. However the
-g flag does work. For a 1920x1200 display you can pass a geometry of
271x82 and you'll get a maximised frame.
I prefer to use code to set this up, I use the following snippet to maximise emacs when started, the benefit is that no matter the display geometry I always get emacs to display as expected.
(let ((px (display-pixel-width))
(setq tx (- (/ px fx) 7))
(setq ty (- (/ py fy) 4))
(setq initial-frame-alist '((top . 2) (left . 2)))
(add-to-list 'default-frame-alist (cons 'width tx))
(add-to-list 'default-frame-alist (cons 'height ty)))
I'm sure there are other ways to do this, maybe better ways, but this is enough for my needs.