The XkbFreeServerMap function frees the specified components of server map in the XkbDescRec structure specified by the xkb parameter and sets the corresponding structure component values to NULL. The which parameter specifies a combination of the server map masks and is a bitwise inclusive OR of the masks listed in Table 1. If free_all is True, which is ignored and XkbFreeServerMap frees every non-NULL structure component in the server map, frees the XkbServerMapRec structure referenced by the server member of the xkb parameter, and sets the server member to NULL.
| Table 1 XkbAllocServerMap Masks | |
| Mask | Effect | 
| XkbExplicitComponentsMask | The min_key_code and max_key_code fields of the xkb parameter are used to
allocate the explicit field of the server map. | 
| XkbKeyActionsMask | The min_key_code and max_key_code fields of the xkb parameter are used to 
allocate the key_acts 
field of the server map. The count_acts parameter is used to allocate the acts 
field of the 
server map. | 
| XkbKeyBehaviorsMask | The min_key_code and max_key_code fields of the xkb parameter are used to 
allocate the behaviors 
field of the server map. | 
| XkbVirtualModMapMask | The min_key_code and max_key_code fields of the xkb parameter are used to 
allocate the vmodmap 
field of the server map. | 
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.
| Table 2 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) | 
The Xkb server map contains the information the server needs to interpret key events and is of type XkbServerMapRec:
#define XkbNumVirtualMods          16
typedef struct {                    /* Server Map */
    unsigned short    num_acts;     /* # of occupied entries in acts */
    unsigned short    size_acts;    /* # of entries in acts */
    XkbAction *       acts;         /* linear 2d tables of key actions, 1 per keycode */
    XkbBehavior *     behaviors;    /* key behaviors,1 per keycode */
    unsigned short *  key_acts;     /* index into acts, 1 per keycode */
    unsigned char *   explicit;     /* explicit overrides of core remapping, 1 per key */
    unsigned char     vmods[XkbNumVirtualMods]; /* real mods bound to virtual mods */
    unsigned short *  vmodmap;      /* virtual mods bound to key, 1 per keycode*/
} XkbServerMapRec, *XkbServerMapPtr;