Re: [Help-smalltalk] C Callouts issue

[Stephen Woolerton]

> OKay, so you would like to have something like a intOut.. or does
> CInt help here? Sorry, I am guessing. Or something like #selfSmallalk?
>
>         holger
Thanks holger.

I had two issues in the last post.
One was a typo, the call to initializeNote was missing a # in the 
definition, i.e. #(#self)

However, I am still working on how to pass a "pointer to an unsigned 
int" as a C callout. The page 
http://www.gnu.org/software/smalltalk/manual/gst.html#C-data-types shows 
how to pass a pointer to a scalar when in a struct, e.g. (#example (#ptr 
#long)).
So I changed my script to have a similar definition:

  CNote class >> newBlankNote: retVal [
     <cCall: 'newBlankNote' returning: #{CNote} args: #((#ptr #uint)>
  ]

And here is the result when the library is called... (the first two 
lines come from printf statements inside the C library. The second line 
shows that the pointer was not actually passed into the library, it is nil)

 Inside newBlankNote: Size in bytes allocated to struct 'Note': 8
 Inside newBlankNote: resultCode pointer: [(nil)]
./ccall2.st:30: Aborted
./ccall2.st:30: Error occurred while not in byte code interpreter!!
/usr/local/lib64/libgst.so.7(+0x71ca7)[0x7f8d8d996ca7]
/lib64/libc.so.6(+0x37c50)[0x7f8d8ceb2c50]
/lib64/libc.so.6(gsignal+0x35)[0x7f8d8ceb2bd5]
/lib64/libc.so.6(abort+0x17b)[0x7f8d8ceb404b]
/usr/local/lib64/libgst.so.7(+0x2c9bb)[0x7f8d8d9519bb]
/usr/lib64/libsigsegv.so.2(+0xe7c)[0x7f8d8cc77e7c]
/lib64/libc.so.6(+0x37c50)[0x7f8d8ceb2c50]
/home/stephenw/devel_gst/ccall2/bug1/libccall2.so(newBlankNote+0x74)[0x7f8d8b7196d0]
/usr/lib64/libffi.so.6(ffi_call_unix64+0x4c)[0x7f8d8ca74ecc]
/usr/lib64/libffi.so.6(ffi_call+0x19d)[0x7f8d8ca7489d]
Aborted

Regards
Stephen