Nick Glencross wrote:
Guys,
As mentioned on the list yesterday I started evaluating ffcall as a
way of providing NCI functionality.
I seem to be seeing rather strange, and it's probably a misunderstanding
on my part.
I've pinched the GET_NCI_x(n) macros and accompanying get_nci_x
functions from nci.c, but they don't seem to be working consistently.
In particular, where I have a signature "pp" I often seem to be getting
the same pointer twice.
If the following line is added as line 267 in nci_ffcall.c after
applying the patch:
printf ("Pointer is %p\n", nci_args->args[i]._pointer);
and the following script run:
.sub test :main
.local pmc libnci_test
libnci_test = loadlib "libnci_test"
.local pmc nci_cb_C1
nci_cb_C1 = dlfunc libnci_test, "nci_cb_C1", "vpp"
.local pmc user_data
user_data = new .Integer
user_data = -99
.local pmc cb
cb = newsub _call_back
.local pmc cb_wrapped
cb_wrapped = new_callback cb, user_data, "iii"
nci_cb_C1 (user_data, cb_wrapped)
.end
.sub _call_back
print "Hello world!\n"
.end
then you get
Pointer is 0x84a33d0
Pointer is 0x84a33d0
[probably a segfault!]
while these are meant to be different addresses (corresponding to
user_data and cb_wrapped). From what I've seen you get the second
address twice.
I must be doing something wrong as it works in nci.c.
Any thoughts would be appreciated as I can't see the wood from the trees
anymore,
Cheers,
Nick
p.s. Since posting the patch, I've realised that I probably need another
Parrot_init_arg_nci(interpreter, &st, nci_args->signature_parrot);
before reading back the values, and probably a 'default' in the switch
which steps over skipped items. This only enables one extra test to
succeed though.
