On Feb 25, 2007, at 6:28 PM, Andy Dent wrote: > Whilst the Count downto 1 idiom is faster for things like skimming > through arrays, in this case isn't it a bit unsafe if the size of the > directory changes through other means whilst you are deleting? > > How much slower is 1 to Count for directories?
The "Count DownTo 1" idiom is used not because of speed but because this is a routine to delete files. If you go the other direction, starting with 1 and going to Count, you will find that when you are done you have deleted only half of the files. Think about it, when you delete the first file, all the remaining files shift down such that when you now reference 2 in your loop you will actually end up with what was originally the third file and so the original second file is not deleted etc. etc. As to your question about the possibility of other processes making changes to this same directory it depends on the directory I would guess. If it is some directory used only by the program that is running the file deletion routine I doubt if you need to worry about this. If it is some directory shared by many processes it could possibly be a problem, for several reasons. === A Mac addict in Tennessee === _______________________________________________ Unsubscribe or switch delivery mode: <http://www.realsoftware.com/support/listmanager/> Search the archives: <http://support.realsoftware.com/listarchives/lists.html>
