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

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

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