Tue, 08/05/2003 - 18:59#2

Anonymous

Motif on 64-bit Sun

I have been playing with this myself some, and I am finding all sorts of problems that are specific to big-endian systems, which would silently succeed on 32-bit systems.

In particular, my interest has to do with portability of the uid files that a 64-bit uil compiler would generate. In particular, portability between a Sun and Itanium.

The most glaring example is that the IDBResource and MrmResource_id structures are oftentimes used interchangably, and yet on a 64-bit platform IDBResource remains a 4 byte quantity, and MrmResource_id becomes an 8 byte quantity. On a little-endian system, this would tend to silently succeed in many cases, but on a big-endian system it causes all sorts of grief.

At the moment for my own testing, I have widened IDBResource to match MrmResource_id. Thus unfortunately leads to other problems - namely that an IDBResource is commonly cast to an IDBridDesc structure, and if you widen one, you have to widen the other. Again, on a little-endian systemm, this would probably still be fine as the top bytes are both unused and ignored. In the sections of code that I am in, the only attempt to deal with alternative architectures are #ifdef WORD64 - thus someone got it working on a Cray, but as best I can tell nobody has tried this on Sun yet.

I would be interested in knowing how other vendors have handled 64-bit Motif, especially on a big-endian system. Hell, even on little-endian systems.