Display *display;
XDevice *device;
XModifierKeymap *modmap;
XModifierKeymap *XGetDeviceModifierMapping(display, device)
Display *display;
XDevice *device;
The modifiermap member of the XModifierKeymap structure contains eight sets of max_keypermod KeyCodes, one for each modifier in the order Shift, Lock, Control, Mod1, Mod2, Mod3, Mod4, and Mod5. Only nonzero KeyCodes have meaning in each set, and zero KeyCodes are ignored. In addition, all of the nonzero KeyCodes must be in the range specified by min_keycode and max_keycode as returned by XListInputDevices, or a BadValue error results. No KeyCode may appear twice in the entire map, or a BadValue error results.
An X server can impose restrictions on how modifiers can be changed, for example, if certain keys do not generate up transitions in hardware, if auto-repeat cannot be disabled on certain keys, or if multiple modifier keys are not supported. If some such restriction is violated, the status reply is MappingFailed, and none of the modifiers are changed. If the new KeyCodes specified for a modifier differ from those currently defined and any (current or new) keys for that modifier are in the logically down state, XSetDeviceModifierMapping returns MappingBusy, and none of the modifiers is changed.
XSetDeviceModifierMapping can generate BadLengthP, BadDevice, BadMatch, BadAlloc, and BadValue errors.
The XGetDeviceModifierMapping request returns a pointer to a newly created XModifierKeymap structure that contains the keys being used as modifiers. The structure should be freed after use by calling XFreeModifierMapping . If only zero values appear in the set for any modifier, that modifier is disabled.
XGetDeviceModifierMapping can generate BadDevice and BadMatch errors.
typedef struct {
int max_keypermod;
KeyCode *modifiermap;
} XModifierKeymap;