| Value | Meaning |
|---|---|
| PRIMARY_ACCELERATOR0 | the primary modifier used to invoke menu accelerators. |
| CONTEXT_MENU1 | the modifier used to invoke context menus. Note that mouse button 3 always triggers context menus. When this modifier is not 0, it additionally triggers context menus when used with mouse button 1. |
| EXTEND_SELECTION2 | the modifier used to extend selections using modifier-click or modifier-cursor-key |
| MODIFY_SELECTION3 | the modifier used to modify selections, which in most cases means toggling the clicked item into or out of the selection. |
| NO_TEXT_INPUT4 | when any of these modifiers is pressed, the key event cannot produce a symbol directly. This is meant to be used for input methods, and for use cases like typeahead search. |
| SHIFT_GROUP5 | the modifier that switches between keyboard groups (AltGr on X11/Windows and Option/Alt on OS X). |
This enum is used with gdk_keymap_get_modifier_mask() in order to determine what modifiers the currently used windowing system backend uses for particular purposes. For example, on X11/Windows, the Control key is used for invoking menu shortcuts (accelerators), whereas on Apple computers it’s the Command key (which correspond to %GDK_CONTROL_MASK and %GDK_MOD2_MASK, respectively).