Re: [Vala] Array parameter calling conventions

[Maciej Piechotka <uzytkownik2 gmail com>]

Walter Mundt wrote:

> I've noticed that in VAPI files, there seems to only be two calling
> conventions for array-type parameters: with and without the length and
> size params passed.
>
> To make it cleaner to bind to C libraries, it would be nice to have a
> more flexible way to specify this.  How hard/desirable would it be to
> add a CCode spec that operates vaguely like this:
>
> Base function, and call in Vala:
>   public static void foo(int[] bar);
>   int[] mybar;
>   foo(mybar);
>
> Variant A:
>   public static void foo([CCode(array_params="length,ptr")]int[] bar);
> generates:
>   foo(mybar_length, mybar);
>
> Variant B:
>   public static void foo([CCode(array_params="ptr,size")]int[] bar);
> generates:
>   foo(mybar, mybar_size); // some C API's want a byte count
>                           // rather than an element count
>
>
> This would allow you to write a VAPI file that seamlessly passes
> whatever array length/size information is desired in whatever order the
> pre-existing C declaration wants it, as long as the size parameter is in
> some way adjacent to the actual array pointer.

I'd like to add it would be nice to have support for passing two arrays
of the same length - at least in VAPI.

Regards
-- 
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