Re: [Vala] Generating bindings for non-GLib/GObject based API

[Michael Wild <themiwi users sourceforge net>]

On 22. Apr, 2010, at 16:12 , Abderrahim Kitouni wrote:

> Hello,
>
> 2010/4/22 Michael Wild <themiwi users sourceforge net>:
> > > I don't understand this, does the function still alocate the instance,
> > > or does it just initialize it?
> >
> > It does both, it just doesn't return the result in the return argument, but in one of the parameters. I 
> > found an example with the same issue, but I don't understand how Vala can be doing the right thing. 
> > Looking at zlib.vapi I see
> >
> > [CCode (cname = "z_stream", destroy_function = "deflateEnd")]
> > public struct DeflateStream : Stream {
> >    [CCode (cname = "deflateInit")]
> >    public DeflateStream (int level = Level.DEFAULT_COMPRESSION);
> >    // ...
> > }
> >
> > but deflateInit has the following (sanitized) signature:
> >
> > int deflateInit(z_stream *strm, int level);
> >
> > How does Vala know that it must pick the first argument and not the return value?
> Because the function doesn't allocate the struct, only initializes it.
> So it's used :
>
> z_stream strm;
> deflateInit(&strm, ...);
>
> this way you have to declare your type as a struct (and not a class).
>
> HTH,
> Abderrahim

Ahh, I see. No, in my case the function definitely does the allocation. Is there any way to make Vala work 
with this function or do I need some wrapper function? How would I best do this?


Michael