[Gtk-sharp-list] Cross Platform Assemblies?

[Jonathan Pryor]

Actually, I am not aware of any 64-bit platform that has 64-bit ints.

ILP64 (where ints, longs, and pointers are 64-bits) has been rejected
(AFAIK) because it's wasteful of space.  Most ints don't need to be
64-bits, so this would increase the size of most code for little
benefit.

LP64 (where longs and pointers are 64-bits) makes more sense to lots of
people.  See:

	http://www.opengroup.org/public/tech/aspen/lp64_wp.htm

There's also P64 (where only pointers are 64-bits, and 64-bit integers
get a new keyword, such as __int64 or "long long int"), which is what
Win64 is supposedly using, primarily because of backward compatibility
reasons (IIRC; much Windows code assumes that
sizeof(INT)==sizeof(LONG)).

So, for the int data type, this is likely not a problem.  The use of
longs could introduce the problem (LP64 vs. P64), but I don't know if
(or how much) longs are used in Gtk+.

 - Jon

On Sun, 2003-03-16 at 02:53, Charles Iliya Krempeaux wrote:
> Hello,
> 
> Looking at GLib's "gtypes.h", I see definitions like:
> 
>     typedef char   gchar;
>     typedef short  gshort;
>     typedef long   glong;
>     typedef int    gint;
>     typedef gint   gboolean;
> 
>     typedef unsigned char   guchar;
>     typedef unsigned short  gushort;
>     typedef unsigned long   gulong;
>     typedef unsigned int    guint;
> 
>     typedef float   gfloat;
>     typedef double  gdouble;
> 
> Now, what this means is that something like a "gint" is going to be a 
> different size on different platforms.  (On a x86 architecture it will
> be 32 bits wide.  On something else it may be 64 bits wide.)
> 
> Now, in the Gtk# code, we have DllImport statements all over the
> place that make assumptions about the size of these things.
> For instance, we have the C declaration:
> 
>     void gtk_widget_set_size_request (GtkWidget *widget,
>                                       gint       width,
>                                       gint       height);
> 
> 
> And in the Gtk#, this gets turned into:
> 
>                 [DllImport("libgtk-win32-2.0-0.dll")]
>                 static extern
>                 void gtk_widget_set_size_request(IntPtr raw,
>                                                  int width,
>                                                  int height);
> 
> Now, this says that a C# "int" is the same as a C "gint".
> 
> Now, on a 32 bit architecture this is true.  But, on a 64 bit
> architecture, this isn't!!!
> 
> This is because, on a 64 bit architecture, a C "gint" will be
> 64 bits wide.  But the .NET "int" will still be 32 bits wide
> (since it is an alias for "System.Int32".)
> 
> Thus we seem to have a problem.
> 
> This will likely require us to build 32 bit versions, 64 bit versions,
> and possible other size versions, of all our assemblies.  (And maybe
> create stub .dll's that link to the correct one at runtime.)
> 
> 
> See ya