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

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