XkbGetMap - Man Page

XkbDescPtr XkbGetMap (Display *display, unsigned int which, unsigned int device_spec);

display

connection to X server

which

mask selecting subcomponents to populate

device_spec

device_id, or XkbUseCoreKbd

Xkb provides two functions to obtain the keyboard mapping components from the  server. The  first function, XkbGetMap, allocates an XkbDescRec structure, retrieves mapping components from the server,  and  stores them in the XkbDescRec structure it just allocated. The second function, XkbGetUpdatedMap, retrieves mapping components from the server and stores them in an XkbDescRec  structure  that has previously been allocated.

To allocate an XkbDescRec structure and populate it with the server's keyboard  client map  and server map, use XkbGetMap. XkbGetMap is similar to XkbGetKeyboard, but is used only for obtaining the address of an XkbDescRec structure that is  populated  with keyboard mapping components. It allows finer control over which  substructures of the  keyboard mapping components are to be populated. XkbGetKeyboard always returns fully populated components, while XkbGetMap can be instructed to return a partially populated component.

The which mask is a bitwise inclusive OR of the masks defined in Table 14.1. Only those  portions of the keyboard server map and the keyboard client maps that are  specified in which are allocated and populated.

In addition to allocating and obtaining the server map and the client map, XkbGetMap also sets the device_spec, the min_key_code, and max_key_code fields of the keyboard description.

XkbGetMap is synchronous; it queries the server for the desired information, waits for a  reply, and  then returns. If successful, XkbGetMap returns a pointer to the XkbDescRec structure it allocated. If unsuccessful, XkbGetMap returns NULL. When unsuccessful, one of the following protocol errors is also  generated:  BadAlloc (unable to allocate the XkbDescRec structure), BadValue (some mask bits  in which are undefined), or BadImplementation (a compatible version of the Xkb extension  is not  available in the server). To free the returned data, use XkbFreeKeyboard.

Xkb also provides convenience functions to get partial component definitions  from the  server. These functions are specified in the "convenience functions" column in  Table  1. Refer to the sections listed in the table for more information on these  functions.

Xkb defines combinations of these masks for convenience:
   
   #define XkbResizableInfoMask   (XkbKeyTypesMask)
   #define XkbAllClientInfoMask   (XkbKeyTypesMask | XkbKeySymsMask |
                                   XkbModifierMapMask)
   #define XkbAllServerInfoMask   (XkbExplicitComponentsMask |
                                   XkbKeyActionsMask | 
                                   XkbKeyBehaviorsMask |
                                   XkbVirtualModsMask | 
                                   XkbVirtualModMapMask)
   #define XkbAllMapComponentsMask XkbAllClientInfoMask | 
                                   XkbAllServerInfoMask)

Key types, symbol maps, and actions are all interrelated: changes in one require  changes  in the others. The convenience functions make it easier to edit these components  and  handle the interdependencies.

The complete description of an Xkb keyboard is given by an XkbDescRec. The  component  structures in the XkbDescRec represent the major Xkb components.

typedef struct {
   struct _XDisplay * display;      /* connection to X server */
   unsigned short     flags;        /* private to Xkb, do not modify */
   unsigned short     device_spec;  /* device of interest */
   KeyCode            min_key_code; /* minimum keycode for device */
   KeyCode            max_key_code; /* maximum keycode for device */
   XkbControlsPtr     ctrls;        /* controls */
   XkbServerMapPtr    server;       /* server keymap */
   XkbClientMapPtr    map;          /* client keymap */
   XkbIndicatorPtr    indicators;   /* indicator map */
   XkbNamesPtr        names;        /* names for all components */
   XkbCompatMapPtr    compat;       /* compatibility map */
   XkbGeometryPtr     geom;         /* physical geometry of keyboard */
} XkbDescRec, *XkbDescPtr;

The display field points to an X display structure. The flags field is private to the library: modifying flags may yield unpredictable results. The device_spec field specifies the device identifier of the keyboard input device, or  XkbUseCoreKeyboard, which specifies the core keyboard device. The min_key_code and max_key_code fields specify the least and greatest keycode that can be returned by the  keyboard.

Each structure component has a corresponding mask bit that is used in function  calls to  indicate that the structure should be manipulated in some manner, such as  allocating it  or freeing it. These masks and their relationships to the fields in the  XkbDescRec are  shown in Table 2.

XkbChangeTypesOfKey(3), XkbCopyKeyType(3), XkbCopyKeyTypes(3), XkbFreeClientMap(3), XkbGetKeyActions(3), XkbGetKeyBehaviors(3), XkbGetKeyboard(3), XkbGetKeyExplicitComponents(3), XkbGetKeyModifierMap(3), XkbGetKeySyms(3), XkbGetKeyTypes(3), XkbGetUpdatedMap(3), XkbGetVirtualModMap(3), XkbGetVirtualMods(3), XkbResizeKeyActions(3), XkbResizeKeySyms(3), XkbResizeKeyType(3)

XChangeKeyboardControl(3), XChangeKeyboardMapping(3), XkbAllocClientMap(3), XkbVirtualModsToReal(3).