[cffi-devel] Patch: FOREIGN-FUNCALL for LispWorks

[Edi Weitz]

Hi!

Attached is a hasty patch to enable CFFI-SYS:%FOREIGN-FUNCALL and
CFFI-SYS:%FOREIGN-FUNCALL-POINTER for LispWorks.  The idea is to
create one foreign funcallable per signature and cache those in a hash
table.  I took a quick glance at the source code of CMUCL's
ALIEN-FUNCALL and my impression (not really understanding the details)
was that CMUCL actually does something similar internally - it creates
a "stub" if necessary, depending on the types.  As you can observe at
the REPL it compiles /something/ when ALIEN-FUNCALL is called.

Granted, it is kind of ugly to call FLI:DEFINE-FOREIGN-FUNCALLABLE in
non-top-level position but I think this solution is better than
nothing.  It looks to me as if FOREIGN-FUNCALL is mostly intended for
interactive use and for "one-shot" invocations - correct me if I'm
wrong.

I don't know if CMUCL's "stubs" will ever be garbage-collected, the
foreign funcallables in my patch certainly won't.  I don't expect this
to be a big problem, though.

I tried the CFFI test suite and it basically ran through with three
exceptions - FUNCALL.FLOAT, DEREF.FLOAT.2, and DEREF.FLOAT.3.  My
guess is that these are due to LispWorks identifying FLOAT and
DOUBLE-FLOAT and are not related to my patch.

Two minor quibbles, unrelated:

1. The documentation says it is only about the cffi-luis branch but it
   seems to me that the main branch and cffi-luis are almost identical
   - or did I miss something?

2. This form

    (define-foreign-library libcurl
      (:unix (:or "libcurl.so.3" "libcurl.so"))
      (t (:default "libcurl")))

   in the (very nice, BTW) tutorial didn't work for me on Linux,
   neither with LispWorks nor with CMUCL.  I had to remove the second
   (:UNIX) line to make it work.

     edi at vmware:~$ ls -l /usr/lib/libcurl*
     lrwxrwxrwx  1 root root     16 Dec 28 19:29 /usr/lib/libcurl.so.3 -> libcurl.so.3.0.0
     -rw-r--r--  1 root root 196632 Dec  7 12:39 /usr/lib/libcurl.so.3.0.0

Cheers,
Edi.

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