Table of Contents

## Name

XChangeKeyboardMapping, XGetKeyboardMapping, XDisplayKeycodes, XSetModifierMapping, XGetModifierMapping, XNewModifiermap, XInsertModifiermapEntry, XDeleteModifiermapEntry, XFreeModifierMap XModifierKeymap - manipulate keyboard encoding and keyboard encoding structure

## Syntax

int XChangeKeyboardMapping(Display *display, int first_keycode,
  int keysyms_per_keycode, KeySym *keysyms, int num_codes);
KeySym *XGetKeyboardMapping(Display *display, KeyCode
  first_keycode, int keycode_count, int *keysyms_per_keycode_return);
int XDisplayKeycodes(Display *display, int
  *min_keycodes_return, int *max_keycodes_return);
int XSetModifierMapping(Display *display, XModifierKeymap
  *modmap);
XModifierKeymap *XGetModifierMapping(Display *display);
XModifierKeymap *XNewModifiermap(int max_keys_per_mod);
XModifierKeymap *XInsertModifiermapEntry(XModifierKeymap *modmap,
  KeyCode keycode_entry, int modifier);
XModifierKeymap *XDeleteModifiermapEntry(XModifierKeymap *modmap,
  KeyCode keycode_entry, int modifier);
int XFreeModifiermap(XModifierKeymap *modmap);

## Arguments

display
  Specifies the connection to the X server.
first_keycode
  Specifies the first KeyCode that is to be changed or returned.
keycode_count
  Specifies the number of KeyCodes that are to be returned.
keycode_entry
  Specifies the KeyCode.
keysyms
  Specifies an array of KeySyms.
keysyms_per_keycode
  Specifies the number of KeySyms per KeyCode.
keysyms_per_keycode_return
  Returns the number of KeySyms per KeyCode.
max_keys_per_mod
  Specifies the number of KeyCode entries preallocated to the modifiers in the map.
max_keycodes_return
  Returns the maximum number of KeyCodes.
min_keycodes_return
  Returns the minimum number of KeyCodes.
modifier
  Specifies the modifier.
modmap
  Specifies the XModifierKeymap structure.
num_codes
  Specifies the number of KeyCodes that are to be changed.

## Description

The XChangeKeyboardMapping function 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:

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    num_codes * keysyms_per_keycode

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

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    first_keycode + num_codes - 1

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

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    (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. XChangeKeyboardMapping generates a MappingNotify event.

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

XChangeKeyboardMapping can generate BadAlloc and BadValue errors.

The XGetKeyboardMapping function 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 XDisplayKeycodes, or a BadValue error results. In addition, the following expression must be less than or equal to max_keycode as returned by XDisplayKeycodes:

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    first_keycode + keycode_count - 1

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

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    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:

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    (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 XGetKeyboardMapping, use XFree.

XGetKeyboardMapping can generate a BadValue error.

The XDisplayKeycodes function returns the min-keycodes and max-keycodes supported by the specified display. The minimum number of KeyCodes returned is never less than 8, and the maximum number of KeyCodes returned is never greater than 255. Not all KeyCodes in this range are required to have corresponding keys.

The XSetModifierMapping function specifies the KeyCodes of the keys (if any) that are to be used as modifiers. If it succeeds, the X server generates a MappingNotify event, and XSetModifierMapping returns MappingSuccess. X permits at most 8 modifier keys. If more than 8 are specified in the XModifierKeymap structure, a BadLength error results.

The modifiermap member of the XModifierKeymap structure contains 8 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 in the Display structure, 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, XSetModifierMapping returns MappingBusy, and none of the modifiers is changed.

XSetModifierMapping can generate BadAlloc and BadValue errors.

The XGetModifierMapping function 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 XFreeModifiermap. If only zero values appear in the set for any modifier, that modifier is disabled.

The XNewModifiermap function returns a pointer to XModifierKeymap structure for later use.

The XInsertModifiermapEntry function adds the specified KeyCode to the set that controls the specified modifier and returns the resulting XModifierKeymap structure (expanded as needed).

The XDeleteModifiermapEntry function deletes the specified KeyCode from the set that controls the specified modifier and returns a pointer to the resulting XModifierKeymap structure.

The XFreeModifiermap function frees the specified XModifierKeymap structure.

## Structures

The XModifierKeymap structure contains:

    0
    0>=40 .vs 0u
    0<=39 .vs 0p
    typedef struct {
        int max_keypermod;    /* This server's max number of keys per modifier */
        KeyCode *modifiermap;    /* An 8 by max_keypermod array of the modifiers */
    } XModifierKeymap;

## Diagnostics

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

## See Also

XFree(3X11) , XSetPointerMapping(3X11)
Xlib - C Language X Interface

Table of Contents

- Name
- Syntax
- Arguments
- Description
- Structures
- Diagnostics
- See Also