On 5/4/06, Heath Johns <address@hidden> wrote:
> I've got a noob question: Why does this segfault? Should I be doing
> this differently? I'm using 2.3 stable on linux...
Hi!
No noob question at all. You've found a genuine bug: the result
type conversion didn't do the right thing for null pointers (#f).
Here is a patch to compiler.scm:
891,893c891,900
< ,@(if (memq rtype
'(nonnull-c-string c-string))
< `((##sys#make-c-string
(let () ,@(cddr lam))))
< (cddr lam)) )
---
> ,@(case rtype
> ((nonnull-c-string)
`((##sys#make-c-string (let () ,@(cddr lam)))))
> ((c-string*)
> (##sys#syntax-error-hook
> "`c-string*' is not a valid
resulte type for callback procedures"
> name) )
> ((c-string)
> `((let ((r (let () ,@(cddr
lam))))
> (and r
(##sys#make-c-string r)) ) ) )
> (else (cddr lam)) ) )
BTW, I recommend using `define-external' (as suggested by Thomas).
In fact I undocumented `foreign-safe-wrapper' and it wil be
deprecated in future releases, since it is kludgy and not really
useful.
(that c-string* works is a mere coincedence - the special treatment of
strings as callback-results didn't take `c-string*' into account).
Thanks for reporting this!
(felix)