Re: c2ada bug report filed

[Simon Wright <simon@pushface.org>]

Per Sandberg <per.sandberg@bredband.net> writes:

> So i expect c2ada to be obsolete at least when GNAT GPL 2011 is
> released.

GNAT GPL 2010 certainly tries; I don't know how good it is.

Just tried on <tcl.h>; GPL 2010 is better than FSF 4.6.0, which didn't
understand
  #define TCL_MAJOR_VERSION 8
for example.

Both made a - to my eyes - strange choice about parameter passing:

   typedef struct Tcl_Interp {
       ...
   } Tcl_Interp;

translated as

   type Tcl_Interp is record
      ...
   end record;
   pragma Convention (C_Pass_By_Copy, Tcl_Interp);

Now, the C code that's being called most certainly doesn't expect
pass-by-copy; and the generated binding always says (eg)

   function Tcl_AppInit (arg1 : access Tcl_Interp) return int;

Wouldn't pragma Convention (C) have done?


For interest, the tcladashell equivalent (which, I believe, was
originally generated using c2ada, but has since been heavily
hand-amended) is

   type Tcl_Interp_Rec (<>) is private;
   type Tcl_Interp is access all Tcl_Interp_Rec;
   pragma Convention (C, Tcl_Interp);

   function Tcl_AppInit (interp : in Tcl_Interp) return C.int;

I shall have a think about this, the 'access' approach is certainly
neat. There's the question of whether null is allowed; if it is, and
customers are using Ada95, 'access' is ruled out.