Hi,
Andy Wingo <wi...@pobox.com> writes:
> You added a change to foreign-set! for %null-pointer. Would it not make
> sense instead to make foreign pointers of type "void" unsettable?
Not necessarily. See the test that was added:
--8<---------------cut here---------------start------------->8---
(pass-if "foreign-set! other-null-pointer"
(let ((f (bytevector->foreign (make-bytevector 2))))
(and (not (= 0 (foreign-ref f)))
(begin
(foreign-set! f 0)
(= 0 (foreign-ref f)))
(begin
;; Here changing the pointer value of F is perfectly valid.
(foreign-set! f 777)
(= 777 (foreign-ref f))))))
--8<---------------cut here---------------end--------------->8---
Here a ((void *) 777) pointer is created.
However, this is not allowed for ‘%null-pointer’ because (1) that would
change its semantics, and (2) it’s defined as ‘const’ anyway, so
modifying it leads to a segfault.
Thanks,
Ludo’.
