Re: [Vala] CCode array length field name

[Evan Nemerson <evan coeus-group com>]

On Mon, 2009-11-30 at 23:45 +0100, pHilipp Zabel wrote:
> On Mon, Nov 30, 2009 at 10:19 PM, Jan-Jaap van der Geer
> <jjvdgeer inbox com> wrote:
> > On Sun, 2009-11-29 at 00:38 +0100, pHilipp Zabel wrote:
> > > > vapi binding:
> > > >
> > > > public class SomeStruct {
> > > > [CCode (array_param_name?...)] // what should this be ?
> > >
> > > [CCode (array_length_name = "dataLength", array_length_type = "size_t")]
> > >
> > > Not sure if that should be size_t or gsize.
> >
> > I have something related. I have the following struct in C:
> >
> > typedef struct
> > {
> >  int errnum;
> >  char errmess[252];
> > } os_error;
> >
> > Right now I have this vapified like this:
> >
> > [CCode (cname == "os_error")]
> > public struct error
> > {
> >  public unowned int errnum;
> >  public unowned char[] errmess;
> > }
> >
> > However, when accessing the error.errmess.length I get compilation
> > errors (in C,, not in Vala. error: 'os_error' has no member named
> > 'errmess_length1'). I suppose this is due to a problem in the vapi, but
> > I am not really sure how to tell Vala the length is 252 bytes.
> >
> > I tried prefixing the errmess member with:
> > [CCode (array_length_name = "252", array_length_type = "int")]
> > but that did not seem to make a difference.
> >
> > Any ideas?
>
> [CCode (array_length = false)] will make Vala turn errmess.length into
> constant -1 instead of errmess_length1. I don't know of any way to
> make that constant 252 instead.

IIRC this should do the trick:

[CCode (cname == "os_error")]
public struct error {
  public unowned int errnum;
  public unowned char errmess[252];
}

> If errmess is null-terminated and utf-8 encoded, you could wrap it as
> a weak string.

I agree, binding it as a string is likely the right way to go. 


-Evan