Manual Reference Pages  - XkbKeyNumGroups (3)


XkbKeyNumGroups - Returns the number of groups of symbols bound to the key corresponding to keycode




int XkbKeyNumGroups (XkbDescPtr xkb, KeyCode keycode);    


- xkb Xkb description of interest
- keycode
  keycode of interest


The group_info field of an XkbSymMapRec is an encoded value containing the number of groups of symbols bound to the key as well as the specification of the treatment of out-of-range groups. It is legal for a key to have zero groups, in which case it also has zero symbols and all events from that key yield NoSymbol. To obtain the number of groups of symbols bound to the key, use XkbKeyNumGroups. To change the number of groups bound to a key, use XkbChangeTypesOfKey. To obtain a mask that determines the treatment of out-of-range groups, use XkbKeyGroupInfo and XkbOutOfRangeGroupInfo.

The keyboard controls contain a groups_wrap field specifying the handling of illegal groups on a global basis. That is, when the user performs an action causing the effective group to go out of the legal range, the groups_wrap field specifies how to normalize the effective keyboard group to a group that is legal for the keyboard as a whole, but there is no guarantee that the normalized group will be within the range of legal groups for any individual key. The per-key group_info field specifies how a key treats a legal effective group if the key does not have a type specified for the group of concern. For example, the Enter key usually has just one group defined. If the user performs an action causing the global keyboard group to change to Group2, the group_info field for the Enter key describes how to handle this situation.

Out-of-range groups for individual keys are mapped to a legal group using the same options as are used for the overall keyboard group. The particular type of mapping used is controlled by the bits set in the group_info flag, as shown in Table 1.

Table 1 group_info Range Normalization
Bits set in group_infoNormalization method
none of the aboveXkbWrapIntoRange

The Xkb extension is composed of two parts: a server extension, and a client-side X library extension. This chapter discusses functions used to modify controls effecting the behavior of the server portion of the Xkb extension. X Library Controls discusses functions used to modify controls that affect only the behavior of the client portion of the extension; those controls are known as Library Controls.

Xkb contains control features that affect the entire keyboard, known as global keyboard controls. Some of the controls may be selectively enabled and disabled; these controls are known as the Boolean Controls. Boolean Controls can be turned on or off under program control and can also be automatically set to an on or off condition when a client program exits. The remaining controls, known as the Non-Boolean Controls, are always active. The XkbControlsRec structure describes the current state of most of the global controls and the attributes effecting the behavior of each of these Xkb features. This chapter describes the Xkb controls and how to manipulate them.

There are two possible components for each of the Boolean Controls: attributes describing how the control should work, and a state describing whether the behavior as a whole is enabled or disabled. The attributes and state for most of these controls are held in the XkbControlsRec structure.

You can manipulate the Xkb controls individually, via convenience functions, or as a whole. To treat them as a group, modify an XkbControlsRec structure to describe all of the changes to be made, and then pass that structure and appropriate flags to an Xkb library function, or use a XkbControlsChangesRec to reduce network traffic. When using a convenience function to manipulate one control individually, you do not use an XkbControlsRec structure directly.

The Xkb controls are grouped as shown in Table 2.

Table 2 Xkb Keyboard Controls
Type of ControlControl NameBoolean Control?
X Version 11 XkbKeyNumGroups (3) libX11 1.5.0
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