|Did you know ...
Support for exchange of wide-character strings is still under
consideration. The functions dealing with 8-bit character strings return
failure when operating on a wide-character atom or Prolog string object.
The functions below can extract and unify both 8-bit and wide atoms and
string objects. Wide character strings are represented as C arrays of
objects of the type
pl_wchar_t, which is guaranteed to be
the same as
wchar_t on platforms supporting this type. For
example, on MS-Windows, this represents a 16-bit UTF-16 string, while
using the GNU C library (glibc) this represents 32-bit UCS4 characters.
it is computed from s using wcslen(). See PL_new_atom()
for error handling.
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
from the source distribution.