XkbGetVirtualMods(3)

NAME

   XkbGetVirtualMods  -  Obtain  a subset of the virtual modifier bindings
   (the vmods array) in a keyboard description

SYNOPSIS

   Status XkbGetVirtualMods (Display *dpy, unsigned int which,  XkbDescPtr
          xkb);

ARGUMENTS

   - dpy  connection to server

   - which
          mask indicating virtual modifier bindings to get

   - xkb  Xkb description where results will be placed

DESCRIPTION

   XkbGetVirtualMods  sends  a  request  to the server to obtain the vmods
   entries for the virtual modifiers specified in  the  mask,  which,  and
   waits for a reply.

   Virtual  modifiers  are  named  by converting their string name to an X
   Atom and storing the Atom in the names.vmods  array  in  an  XkbDescRec
   structure. The position of a name Atom in the names.vmods array defines
   the bit position used to represent the virtual modifier  and  also  the
   index  used  when accessing virtual modifier information in arrays: the
   name in the i-th (0 relative) entry of names.vmods is the i-th  virtual
   modifier,  represented  by  the  mask  (1<<i).  Throughout Xkb, various
   functions have a parameter that is a mask representing virtual modifier
   choices. In each case, the i-th bit (0 relative) of the mask represents
   the i-th virtual modifier.

   To  set  the  name  of  a  virtual  modifier,  use  XkbSetNames,  using
   XkbVirtualModNamesMask  in  which  and the name in the xkb argument; to
   retrieve indicator names, use XkbGetNames.

   For each bit set in which, XkbGetVirtualMods updates the  corresponding
   virtual modifier definition in the server->vmods array of xkb.  The xkb
   parameter must be a pointer to a valid  Xkb  keyboard  description.  If
   successful, XkbGetVirtualMods returns Success.

   Virtual Modifier Names and Masks

   Virtual  modifiers  are  named  by converting their string name to an X
   Atom and storing the Atom in the names.vmods  array  in  an  XkbDescRec
   structure. The position of a name Atom in the names.vmods array defines
   the bit position used to represent the virtual modifier  and  also  the
   index  used  when accessing virtual modifier information in arrays: the
   name in the i-th (0 relative) entry of names.vmods is the i-th  virtual
   modifier,  represented  by  the  mask  (1<<i).  Throughout Xkb, various
   functions have a parameter that is a mask representing virtual modifier
   choices. In each case, the i-th bit (0 relative) of the mask represents
   the i-th virtual modifier.

   To  set  the  name  of  a  virtual  modifier,  use  XkbSetNames,  using
   XkbVirtualModNamesMask  in  which  and the name in the xkb argument; to
   retrieve indicator names, use XkbGetNames.

   If the server  map  has  not  been  allocated  in  the  xkb  parameter,
   XkbGetVirtualMods  allocates  and  initializes  it before obtaining the
   virtual modifier bindings.

   If the server does not have a compatible version of  Xkb,  or  the  Xkb
   extension  has not been properly initialized, XkbGetVirtualMods returns
   BadMatch. Any errors in allocation cause  XkbGetVirtualMods  to  return
   BadAlloc.

RETURN VALUES

   Success        The  XkbGetVirtualMods  function returns Success when it
                  successfully updates the corresponding virtual  modifier
                  definition in the server->vmods array of xkb.

STRUCTURES

   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 1.

           Table 1 Mask Bits for XkbDescRec
   
   Mask Bit               XkbDescRec Field   Value
   
   XkbControlsMask        ctrls              (1L<<0)
   XkbServerMapMask       server             (1L<<1)
   XkbIClientMapMask      map                (1L<<2)
   XkbIndicatorMapMask    indicators         (1L<<3)
   XkbNamesMask           names              (1L<<4)
   XkbCompatMapMask       compat             (1L<<5)
   XkbGeometryMask        geom               (1L<<6)
   XkbAllComponentsMask   All Fields         (0x7f)

DIAGNOSTICS

   BadAlloc       Unable to allocate storage

   BadMatch       A  compatible  version  of  Xkb was not available in the
                  server or an argument has correct type and range, but is
                  otherwise invalid

SEE ALSO

   XkbGetNames(3), XkbSetNames(3)

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