Hi Paul, Thanks for your comments. I go back to the code and to the books then.
Yann 2008/10/27 Paul Kelly <[EMAIL PROTECTED]>: > Hi Yann, > Thought I would comment too so you know it is not just Glynn who sees there > is a problem here. > > On Mon, 27 Oct 2008, Yann Chemin wrote: > >> Hello Glynn, >> >> since I rewrote the code, and tested it, I know quite much what I do >> with the bitshifts, the image input, and the classification resulting >> from bitshifts. >> >> I have not seen so far any need to >>= instead of >>, in any of the >> related code I read. > > Well, it is not in doubt that the statement with the bit shift does not do > anything and has no effect. So if you feel it works OK the way it is then > that statement can be safely removed with no effect. > >> My worry in this email below was that a non-Unix platform compiler >> (which I don't have) would cough on it for some unknown reason to me. > > Whether or not there is a warning is a moot point (apart from the fact that > because we're only finding this bug because of a warning, it suggests there > could be other undiscovered bugs in the code that aren't generating > warnings). Anyway as Glynn said, the point is that a statement like qctemp >>> 2; > does not do anything. qctemp is not modified as a result; the bit-shifted > value theoretically exists in the ether for an instant, but it is not > assigned to anything so it is lost again instantly. That statement can be > removed from the program and the output will be exactly the same. > >> As I can imagine, the compiler would find strange there is no variable >> data allocation in a line of code, but I would expect it to understand >> the unique feature of bitshift too. > > What do you mean? Bitshift doesn't have a unique feature; it works just like > any other operator like + or - or | or &. > > Paul > -- Yann Chemin International Rice Research Institute Office: http://www.irri.org/gis Perso: http://www.freewebs.com/ychemin YiKingDo: http://yikingdo.unblog.fr/ _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
