How to deal with particular key-binding conflict (F3 key on Mac)

Question

I would like to make a very basic macro on my Mac, to have a command that writes a list of slashes in the current file : ////////////////////

The "Basic emacs macros" section of the manual says :

‘<F3>’
     Start defining a keyboard macro
     (‘kmacro-start-macro-or-insert-counter’).
‘<F4>’
     If a keyboard macro is being defined, end the definition;
     otherwise, execute the most recent keyboard macro
(‘kmacro-end-or-call-macro’).

Unfortunately, on my High Sierra Mac the F3 and F4 keys have a builtin "Mission Control" behaviour, so I cannot define macros this way.

How to fix this ?

Answer 1

You can also use C-x ( and C-x ).

Answer 2

By default, on Macs, pressing F3 does the Mission Control behavior as you mentioned. But this isn't because the operating system intercepts the F3 key; it's because pressing that button sends some sort of "Activate Mission Control" keycode.

It turns out that you can use your keyboard to send an F3 keypress! Press Fn+F3, and the keyboard will send the F3 keycode, which Emacs (and other programs) can react to.

From Apple's documentation:

By default, pressing one of these keys performs the special feature indicated by the icon printed on the key. For example, pressing the keys with speaker icons adjusts the volume.

If you want to use one of these keys as a standard function key, hold the Fn key (usually in the lower-left corner of the keyboard) while pressing the function key. For example, pressing Fn-F10 (speaker icon) performs the function assigned to the F10 key instead of toggling mute on or off.

If you would rather the keys work as the standard Fn keys, go to the Keyboard settings page, where there's an option "Use F1, F2, etc. keys as standard function keys". Check that off, then pressing F3 sends an F3 keycode; Mission Control is Fn-F3.