Be warned that this problem is still unsolved, even in the newest ROOT 6.22/08:
@pcanal That’s why I started to “advertise” the usage of “rootlogon.C” files (and they also work in both ROOT 5 and 6 versions, if one needs to maintain this kind of compatibility for one’s macros).
BTW. For safety reasons, I would do both in the “default constructor”, set all pointers and the length to zero (well, you never know when something will try to be clever and use or “delete” them). Also, make sure that you do not allocate anything in the “default constructor” (this space will be lost by the ROOT I/O).