[Vala] Generating vapi file for a simple struct

[Jan-Jaap van der Geer <jjvdgeer inbox com>]

Hello,

I am quite new to Vala. I have ported it to RISC OS but for it to
be of any use I want it to talk to a library called OSLib.

Just to get me started, I tried to create a vapi file for a very
common struct for errors, but I am having difficulties and I
haven't found any relevant documentation about generating vapi
files.

The struct is simply defined as:

struct os_error
   {  bits errnum;
      char errmess [252];
   };

My vapi file looks like this:

[CCode (cheader_filename = "oslib/os.h")]
namespace OSLib
{
  [CCode (cname = "os_error")]
  public struct OSError
  {
    public int errnum;
    public char[252] errmess;
  }
}

And a very simple program to use it:

using GLib;
using OSLib;

public class Test : Object
{
  public static void main(string[] args)
  {
    OSError osError = OSError();
    osError.errnum = 4;
  }
}

The C program that is generated by Vala (0.7.2 in case that
matters) looks like this:

void test_main (char** args, int args_length1) {
        os_error _tmp0_ = {0};
        os_error osError;
        osError = (memset (&_tmp0_, 0, sizeof (os_error)), _tmp0_);
        osError.errnum = 4;
        os_lib_os_error_destroy (&osError);
}

Of course, this last method does not exist, so it does not compile.

What am I doing wrong?

Cheers,
Jan-Jaap