NAME

       XGetDeviceKeyMapping, XChangeDeviceKeyMapping - query or change device key mappings

SYNOPSIS

       #include <X11/extensions/XInput.h>

       KeySym *XGetDeviceKeyMapping( Display *display,
                                     XDevice *device,
                                     KeyCode first_keycode,
                                     int keycode_count,
                                     int *keysyms_per_keycode_return);
       display
              Specifies the connection to the X server.

       device
              Specifies the device whose key mapping is to be queried
              or modified.

       first_keycode
              Specifies the first KeyCode to be returned.

       keycode_count
              Specifies the number of KeyCodes to be returned or
              modified.

       keysyms_per_keycode
              Specifies the number of KeySyms per KeyCode.

       keysyms_per_keycode_return
              Specifies the address of a variable into which the
              number of KeySyms per KeyCodewill be returned.

       keysyms
              Specifies the address of an array of KeySyms.

DESCRIPTION

           For the specified device, the XGetDeviceKeyMapping request
           returns the symbols for the specified number of KeyCodes
           starting with first_keycode. The value specified in
           first_keycode must be greater than or equal to min_keycode as
           returned by XListInputDevices, or a BadValue error results. In
           addition, the following expression must be less than or equal
           to max_keycode as returned by XListInputDevices:

           first_keycode + keycode_count - 1

           If this is not the case, a BadValue error results. The number
           of elements in the KeySyms list is:

           keycode_count * keysyms_per_keycode_return

           KeySym number N, counting from zero, for KeyCode K has the
           following index in the list, counting from zero: (K -
           first_code) * keysyms_per_code_return + N

           The X server arbitrarily chooses the keysyms_per_keycode_return
           value to be large enough to report all requested symbols. A
           special KeySym value of NoSymbol is used to fill in unused
           elements for individual KeyCodes. To free the storage returned
           by XGetDeviceKeyMapping, use XFree.

           If the specified device does not support input class keys, a
           BadMatch error will result.

           XGetDeviceKeyMapping can generate a BadDevice, BadMatch, or
           BadValue error.

           For the specified device, the XChangeDeviceKeyMapping request
           defines the symbols for the specified number of KeyCodes
           starting with first_keycode. The symbols for KeyCodes outside
           this range remain unchanged. The number of elements in keysyms
           must be:

           num_codes * keysyms_per_keycode

           The specified first_keycode must be greater than or equal to
           min_keycode returned by XListInputDevices, or a BadValue error
           results. In addition, the following expression must be less
           than or equal to max_keycode as returned by XListInputDevices,
           or a BadValue error results:

           first_keycode + num_codes - 1

           KeySym number N, counting from zero, for KeyCode K has the
           following index in keysyms, counting from zero:

           (K - first_keycode) * keysyms_per_keycode + N

           The specified keysyms_per_keycode can be chosen arbitrarily by
           the client to be large enough to hold all desired symbols. A
           special KeySym value of NoSymbol should be used to fill in
           unused elements for individual KeyCodes. It is legal for
           NoSymbol to appear in nontrailing positions of the effective
           list for a KeyCode.XChangeDeviceKeyMapping generates a
           DeviceMappingNotify event that is sent to all clients that have
           selected that type of event.

           There is no requirement that the X server interpret this
           mapping. It is merely stored for reading and writing by
           clients.

           If the specified device does not support input class keys, a
           BadMatch error results.

           XChangeDeviceKeyMapping can generate a BadDevice, BadMatch,
           BadAlloc, or BadValue error.

DIAGNOSTICS

           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 XGetDeviceKeyMapping or
                  XChangeDeviceKeyMapping 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.

           BadAlloc
                  The server failed to allocate the requested resource or
                  server memory.

SEE ALSO

           XSetDeviceButtonMapping(3), XSetDeviceModifierMapping(__3_)

                                            03/09/2013                    XGETDEVICEKEYMAPPING(3)