XkbAllocKeyboard - Man Page

XkbDescRec XkbAllocKeyboard (void);

Applications seldom need to directly allocate a keyboard description; calling XkbGetKeyboard usually suffices. In the event you need to create a keyboard description from  scratch, however, use XkbAllocKeyboard rather than directly calling malloc.

If XkbAllocKeyboard fails to allocate the keyboard description, it returns NULL.  Otherwise, it returns a pointer to an empty keyboard description structure. The device_spec field will have been initialized to XkbUseCoreKbd. You may then  either fill in the structure components or use Xkb functions to obtain values  for the structure components from a keyboard device.

malloc(3F), XkbUseCoreKbd(3), XkbGetKeyboard(3)

XkbAllocGeometry(3).