Man page 3 : XkbKeyGroupsWidth

XkbKeyGroupsWidth - Computes the maximum width associated with the key corresponding to keycode

int XkbKeyGroupsWidth (XkbDescPtr xkb , KeyCode keycode );

• - xkb
      Xkb description of interest
• - keycode
      keycode of interest

The key width and number of groups associated with a key are used to form a small two-dimensional array of KeySyms for a key. This array may be different sizes for different keys. The array for a single key is stored as a linear list, in row-major order. The arrays for all of the keys are stored in the symsfield of the client map. There is one row for each group associated with a key and one column for each level. The index corresponding to a given group and shift level is computed as:

     idx = group_index * key_width + shift_level

The offsetfield of the key_sym_mapentry for a key is used to access the beginning of the array. XkbKeyGroupsWidthcomputes the maximum width associated with the key corresponding to keycode.