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XkbKeyNumActions(3)                             XKB FUNCTIONS                            XkbKeyNumActions(3)



NAME
       XkbKeyNumActions - Computes the number of actions associated with the key corresponding to keycode

SYNOPSIS
       int XkbKeyNumActions macro ( xkb, keycode )
             XkbDescPtr xkb;
             KeyCode keycode;

ARGUMENTS
       - xkb  Xkb description of interest

       - keycode
              keycode of interest

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 opti-mize optimize
       mize 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.

       XkbKeyNumActions computes the number of actions associated with the  key  corresponding  to  keycode.
       This should be the same value as the result of XkbKeyNumSyms.

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;


SEE ALSO
       XkbKeyNumSyms(3)



X Version 11                                    libX11 1.2.1                             XkbKeyNumActions(3)