Do you know if it is possible to go the other way around? i.e., array
of ints as an output parameter

So far, I have
attach_function :function2, [:pointer], :int

...

ptr = FFI::MemoryPointer.new(:int, 10)
MyLibrary.function2(ptr)
puts ptr.read_array_of_int(10)

But all it prints out is [0, 0, 0, 0, 0, 0, 0, 0, 0, 0].

Thanks



On Oct 26, 12:46 pm, John Lee <jiujitsu1...@gmail.com> wrote:

> Thanks a lot. Your code really helped!
>
> On Oct 26, 9:35 am, Chuck Remes <cremes.devl...@mac.com> wrote:
>
>
>
>
>
>
>

> > On Oct 26, 2011, at 10:31 AM, John Lee wrote:

>

> > > I tried wrapping my code inside a module, but the problem still
> > > persists.

>

> > > Do you think :pointer is the correct type to represent the array in
> > > attach_function.

>

> > > I know that if you have an array in a struct, you can specify it as:
> > > class Struct1 < ::FFI::Struct
> > >   layout :value1, [:int, 3]
> > > end

>

> > > So I tried to replace :pointer with [:int, 3] in attach_function, but
> > > it complains about "unable to resolve type ':int, 3]' <TypeError>"
> > > attach_function :function1, [[:int, 3], :int, :int], :int

>

> > > Has anyone got arrays to work with FFI?

>

> > I have gotten it working in my own project. Take a look at my definition for a function that takes an array:

>

> >https://github.com/chuckremes/ffi-rzmq/blob/master/lib/ffi-rzmq/libzm...

>

> > I call that function here:

>

> >https://github.com/chuckremes/ffi-rzmq/blob/master/lib/ffi-rzmq/poll....

>

> > The array that is passed to that function is constructed in this file:

>

> >https://github.com/chuckremes/ffi-rzmq/blob/master/lib/ffi-rzmq/poll_...

>

> > In that file, the #clean method is where most of the array work is done where I construct the array.

>

> > I know it's a big example, but it works and has worked without change since the ffi gem was at 0.6.3.

>

> > cr