On Friday, March 02, 2012 05:37:46 Nathan M. Swan wrote: > Am I correct that trying to use an Object null results in > undefined behavior? > > Object o = null; > o.opCmp(new Object); // segmentation fault on my OSX machine > > This seems a bit non-D-ish to me, as other bugs like this throw > Errors (e.g. RangeError). > > It would be nice if it would throw a NullPointerError or > something like that, because I spent a long time trying to find a > bug that crashed the program before writeln-debugging statements > could be flushed.
It's defined. The operating system protects you. You get a segfault on *nix and an access violation on Windows. Walter's take on it is that there is no point in checking for what the operating system is already checking for - especially when it adds additional overhead. Plenty of folks disagree, but that's the way it is. If you really care about checking for it, then just assert: assert(obj !is null); or assert(obj); (the second one will also call the object's invariant). - Jonathan M Davis
