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XkbKeyAction(3)                                 XKB FUNCTIONS                                XkbKeyAction(3)



NAME
       XkbKeyAction -  Returns the key action

SYNOPSIS
       XkbAction XkbKeyAction ( xkb, keycode, idx )
             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 modi-fier. modifier.
       fier.  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 mapping 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 specified
       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  associ-ated associated
       ated 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.

       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  asso-ciated associated
       ciated  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;




X Version 11                                    libX11 1.2.1                                 XkbKeyAction(3)