CLISP - an ANSI Common Lisp

Tom Weissmann asked:

>My question is: is the vector copied to a C array before is it used by
>fwrite, or does fwrite read it directly?

Generally, CLISP does not give the alien world pointers to Lisp data structures. It will copy Lisp array contents onto the C execution stack and pass a pointer to that area.
This should be fast enough for many purposes. Why do you inquire?

Regards,
 Jörg Höhle.

Tom Weissmann wrote:
>avoid using subseq
Did you investigate using displaced arrays? (see MAKE-ARRAY)
I believe they are as fast as original ones and can be passed as well to the FFI.
You can use a sliding window technique with such a displaced array, see ADJUST-ARRAY.

However, for small snippets, simple calls to SUBSEQ may end up being faster
than offset calculations using ADJUST-ARRAY.

Regards,
 Jörg Höhle