Manual Pages for UNIX Operating System command usage for man XkbKeyAction

XKB FUNCTIONS                                  XkbKeyAction(3x11)



NAME
     XkbKeyAction -  Returns the key action

SYNOPSIS
     cc [ flag... ] file... -lX11 [ library... ]

     XkbAction XkbKeyAction (XkbDescPtr xkb, KeyCode keycode, int
          idx);

ARGUMENTS
     - xkb
          Xkb description of interest

     - keycode
          keycode of interest

     - idx
          index for group and shift level

DESCRIPTION
     A key action defines the effect  key  presses  and  releases
     have  on  the internal state of the server. For example, the
     expected key action associated with pressing the  Shift  key
     is  to  set  the  Shift  modifier.  There is zero or one key
     action associated with each keysym bound to each key.

     Just as the entire list of key symbols for the keyboard map-
     ping is held in the syms field of the client map, the entire
     list of key actions for the keyboard mapping is held in  the
     acts  array  of  the  server  map. The total size of acts is
     specified by size_acts, and the number of entries is  speci-
     fied by num_acts.

     The  key_acts  array,  indexed  by  keycode,  describes  the
     actions  associated  with  a  key.  The  key_acts  array has
     min_key_code unused entries at the  start  to  allow  direct
     indexing  using  a  keycode. If a key_acts entry is zero, it
     means the key does not have any actions associated with  it.
     If  an entry is not zero, the entry represents an index into
     the acts field of the server map, much as the  offset  field
     of  a KeySymMapRec structure is an index into the syms field
     of the client map.

     The reason the acts field is a linear list of XkbActions  is
     to  reduce  the memory consumption associated with a keymap.
     Because Xkb allows individual keys to  have  multiple  shift
     levels  and  a  different number of groups per key, a single
     two-dimensional array of KeySyms would potentially  be  very
     large  and  sparse.  Instead,  Xkb  provides  a  small  two-
     dimensional array of XkbActions for each key. To  store  all
     of  these  individual  arrays,  Xkb  concatenates each array
     together in the acts field of the server map.



X Version 11        Last change: libX11 1.3.5                   1






XKB FUNCTIONS                                  XkbKeyAction(3x11)



     The key action structures consist only  of  fields  of  type
     char  or  unsigned  char.  This  is  done  to  optimize data
     transfer when the server sends bytes over the wire.  If  the
     fields  are  anything  but  bytes,  the  server  has to sift
     through all of the actions  and  swap  any  nonbyte  fields.
     Because  they consist of nothing but bytes, it can just copy
     them out.

     XkbKeyAction returns the key action indexed by  idx  in  the
     two-dimensional array of key actions associated with the key
     corresponding to keycode.idx may be computed from the  group
     and shift level of interest as follows:

         idx = group_index * key_width + shift_level

STRUCTURES
     The KeySymMapRec structure is defined as follows:

         #define XkbNumKbdGroups             4
         #define XkbMaxKbdGroup              (XkbNumKbdGroups-1)

         typedef struct {                    /* map to keysyms for a single keycode
     */
             unsigned char       kt_index[XkbNumKbdGroups];  /* key type index for
     each group */
             unsigned char       group_info; /* # of groups and out of range group
     handling */
             unsigned char       width;      /* max # of shift levels for key */
             unsigned short      offset;     /* index to keysym table in syms array
     */
     } XkbSymMapRec, *XkbSymMapPtr;



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | x11/library/libx11          |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | See XInitThreads(3X11)      |
    |_____________________________|_____________________________|








X Version 11        Last change: libX11 1.3.5                   2