Availability:C-language interface function
int PL_unify_wchars_diff(term_t
+t, term_t -tail, int type, size_t len, const pl_wchar_t *s)Difference list version of PL_unify_wchars(),
only supporting the types PL_CODE_LIST and PL_CHAR_LIST.
It serves two purposes. It allows for returning very long lists from
data read from a stream without the need for a resizing buffer in C.
Also, the use of difference lists is often practical for further
processing in Prolog. Examples can be found in packages/clib/readutil.c
from the source distribution.