XkbCopyKeyType copies the key type specified by from to the key type specified by into. Both must point to legal XkbKeyTypeRec structures. Xkb assumes from and into point to different places. As a result, overlaps can be fatal. XkbCopyKeyType frees any existing map, preserve, and level_names in into prior to copying. If any allocation errors occur while copying from to into, XkbCopyKeyType returns BadAlloc. Otherwise, XkbCopyKeyType copies from to into and returns Success.
Key types are used to determine
the shift level of a key given the current state of the keyboard. The set
of all possible key types for the Xkb keyboard description are held in
the types field of the client map, whose total size is stored in size_types,
and whose total number of valid entries is stored in num_types. Key types
are defined using the following structure:
typedef struct { /* Key Type */
XkbModsRec mods; /* modifiers used to compute shift level
*/
unsigned char num_levels; /* total # shift levels, do not modify
directly */
unsigned char map_count; /* # entries in map, preserve (if non-NULL)
*/
XkbKTMapEntryPtr map; /* vector of modifiers for each shift
level */
XkbModsPtr preserve; /* mods to preserve for corresponding
map entry */
Atom name; /* name of key type */
Atom * level_names; /* array of names of each shift level
*/
} XkbKeyTypeRec, *XkbKeyTypePtr;