#include <X11/extensions/XInput.h>
int XSetDeviceModifierMapping( Display *display,
XDevice *device,
XModifierKeymap *modmap);
XModifierKeymap *XGetDeviceModifierMapping( Display *display,
XDevice *device);
display
Specifies the connection to the X server.
device
Specifies the device whose modifier mapping is to be
queried or modified.
modmap
Specifies a pointer to the XModifierKeymap structure.
The XSetDeviceModifierMapping request specifies the KeyCodes of the keys (if any) that are to be used as modifiers for the specified device. If it succeeds, the X server generates a DeviceMappingNotify event, and XSetDeviceModifierMapping returns MappingSuccess. X permits at most eight modifier keys. If more than eight are specified in the XModifierKeymap structure, a BadLength error results.
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 BadLength, 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.
Structures
The XModifierKeymap structure contains:
typedef struct {
int max_keypermod;
KeyCode *modifiermap;
} XModifierKeymap;
BadLength
More than eight keys were specified in the
XModifierKeymap structure.
BadAlloc
The server failed to allocate the requested resource or
server memory.
BadDevice
An invalid device was specified. The specified device
does not exist or has not been opened by this client via
XOpenInputDevice. This error may also occur if the
specified device is the X keyboard or X pointer device.
BadMatch
This error may occur if an XGetDeviceModifierMapping or
XChangeDeviceModifierMapping request was made specifying
a device that has no keys.
BadValue
Some numeric value falls outside the range of values
accepted by the request. Unless a specific range is
specified for an argument, the full range defined by the
argument's type is accepted. Any argument defined as a
set of alternatives can generate this error.