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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 (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 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 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 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.

       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.

       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 1.8.6              XkbKeyNumActions(3)