Hello, I am the author of the _itow tests and the _itow function.
As far as I can remember when I tested the _itow functions under WIN2000 and under XP (No SP or just SP1) it was allowed to call _itow with
_itow(123, NULL, 10)
and the result of this call was NULL.
The wine _itow function implemented this functionality because of "bug by bug" compatibility (Some Applications might be based on this "Feature"). The Test was done to find regressions or changes in the M$ operating systems. In my opinion testing corner cases is important.
What does "there is failure" mean. Does it crash or return something different from NULL. When it crashes under XP SP2 the function _itow should remain unchanged. When some other value (different from NULL) is returned it might be necessary to change _itow.
By the way. The reason I stopped developing for Wine is: I now have my own project:
Seed7
In the Seed7 programming language new statements and operators can be declared easily. Functions with type results and type parameters are more elegant than a template or generics concept.
Look at wikipedia: http://en.wikipedia.org/wiki/Seed7
or at sourceforge: http://sourceforge.net/projects/seed7
Just download Seed7 and see the new concepts.
Greetings Thomas Mertes