Xkb provides a number of functions to allocate and free subcomponents of a keyboard geometry. Use these functions to create or modify keyboard geometries. Note that these functions merely allocate space for the new element(s), and it is up to you to fill in the values explicitly in your code. These allocation functions increase sz_* but never touch num_* (unless there is an allocation failure, in which case they reset both sz_* and num_* to zero). These functions return Success if they succeed, BadAlloc if they are not able to allocate space, or BadValue if a parameter is not as expected.
The values of which and free_all determine how much of the specified geometry is freed. The valid values for which are:
#define XkbGeomPropertiesMask (1<<0)
#define XkbGeomColorsMask (1<<1)
#define XkbGeomShapesMask (1<<2)
#define XkbGeomSectionsMask (1<<3)
#define XkbGeomDoodadsMask (1<<4)
#define XkbGeomAllMask (0x1f)
If free_all is True, the entire geometry is freed regardless of the value
of which. Otherwise, the portions of the geometry specified by which
are freed.