Hi Susan, The solution to your problem is to call TFile::Write after having created your Tree. See an example in the attachement Rene Brun On Tue, 3 Jun 2003, Susan Kasahara wrote: > Hi roottalk, > We are experiencing a problem with our dispatcher/daq configuration when using recent > versions of root. This configuration is such that the daq writes records to root trees which > are autosaved to file at regular intervals. The dispatcher reads the trees from the open > file and serves the data to clients while the data file is still being written to. This system has > worked for us for more than a year at our detector site. > We recently upgraded root at the detector site to v3.04/02. This version (and versions > more recent than this) seems to have a problem when reading open files when the file > has had baskets dumped to it but no trees yet autosaved to it. If the dispatcher should > attempt to read the file when the file is in this state (baskets dumped, but no autosave) the result is: > > Warning in <TNetFile::Init>: file root://daqdcp.minos-soudan.org//F00014618_0000.mdaq.root probably not closed, trying > to recover > Warning in <TNetFile::Init>: no keys recovered, file has been made a Zombie > > This is something new that is different than the previously experienced "normal" response of > > Warning in <TNetFile::Init>: file root://daqdcp.minos-soudan.org//F00014618_0000.mdaq.root has no keys > > which still occurs when the file has been opened by the daq but no keys or basket dumps have been > written to the file. In the latter case, the dispatcher server responds by attempting to read the > file again after a short wait time. I am wondering if it is possible for root to not attempt > to recover the file automatically when the file is open, indicating its still being written to, > as it did in earlier versions of root. > I have also noticed that in the cvs version of root there is a problem when reading from open > files such that I observe error messages of the type: > Error in <TFile::ReadKeys>: reading illegal key, exiting after 0 keys > and the open file is unreadable by the dispatcher because the read of keys from the file is > aborted after this message. This error message was introduced in the > 2003-03-01 version of root. > Thanks for your help, > -Sue K. > >
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