> Hi Valery and Rene,
> I made the following modification to file MainEvent.cxx: I only removed the
> statements in the write case from the MainEvent.cxx file, everything between
> line 166 and line 225. As I had mentioned, I wanted to separate reading and
> writing trees into separate routines.
> I understand that the problem has to do with the dictionary and the shared
> libraries. I used Renes advice and include gSystem->Load("Root_Tree"); in my
> main routine. That solved my problem.
> As a response to Valery: My code had a reference to TTree (TTree *T;), but
> that did not seem to be enough to include the DLL.
I reproduce your problem. To see what is going wrong I edited the line
of ".rootrc" file
# Show where item is found in the specified path
Root.ShowPath: true
Then I started the stand-alone ROOT and got:
E:\users\root\test>root
the current keyboard layout is 866
Which: root.exe = e:\users\root\bin\root.exe
*******************************************
* *
* W E L C O M E to R O O T *
* *
* Version 2.23/11 27 January 2000 *
* *
* You are welcome to visit our Web site *
* http://root.cern.ch *
* *
*******************************************
CINT/ROOT C/C++ Interpreter version 5.14.25, Nov 25 1999
Type ? for help. Commands must be C++ statements.
Enclose multiple statements between { }.
Which: Root_Graf3d.dll = e:\users\root\bin\Root_Graf3d.dll
Which: Root_Tree.dll = e:\users\root\bin\Root_Tree.dll
Which: Root_Matrix.dll = e:\users\root\bin\Root_Matrix.dll
Which: Root_Minuit.dll = e:\users\root\bin\Root_Minuit.dll
Which: Root_Postscript.dll = e:\users\root\bin\Root_Postscript.dll
Which: Root_Html.dll = e:\users\root\bin\Root_Html.dll
--------------------
This shows every thing fine.
Now I launched "Event.exe" from the test subdirectory (with no "write"
branch and got no evidence ROOT did try to load TTree:
E:\users\root\test> Event 400 1 1 20
Error in <TKey::ReadObj>: Unknown class TTree
Very likely MS loader does not map ALL entries for all
DLL's unless one does this "by hand" via gSystem->Load().
It sounds it does load the method TTree::GetBranch() and everything this
method needs to go ahead but missed the Root/Cint dictionary this way.
(I wonder MS employs "ProcessLine" approach to call DLL functions as
ROOT does)
So I guess on different UNIX flavors we can observe something like this too
(or will see in future)
Valery
> Thanks for your help,
>
> Reinhard
>
>
>
> -----Original Message-----
> From: Valeri Fine (Faine) [mailto:fine@bnl.gov]
> Sent: Sunday, January 30, 2000 10:05 AM
> To: Reinhard Schwienhorst
> Cc: Roottalk
> Subject: Re: Error in <TKey::ReadObj>: Unknown class TTree
>
>
>
> > Hi Reinhard,
> > I do not know what you did in MainEvent.cxx.
> > If you remove all the references to TTree or classes in the libTree
> > library,
>
> I wonder one he can not do this. If one removes references how can he use
> it from the compiled code ?
>
> > TTree method
> > you must load explicitely the library at the library at the start of the
> > main program with gSystem->Load("libTree"). On NT, it is not sufficient
> > to specify the library in the list of libs when you link the program.
>
> If code has any reference to TTree it will be linked with Root_Tree.lib
> against of Root_tree.DLL with no extra effort.
> If code has no refs to TTree it can not use TTree anyway on either
> platform.
>
> So it is a dictionary problem not the dynamic library. By some reason CINT
> Dictionary
> reports it doesn't know "TTree" ?
> Was there any change in the way the dictionaty is created recently ?
>
> Valery
>
> >
> > Rene Brun
> >
> >
> > Reinhard Schwienhorst wrote:
> > >
> > > Hi,
> > > I have run into a problem when reading trees from a file with a program
> > > rather than in a macro. I am using the event example from the test area
> and
> > > I have created the event.root file. I modified MainEvent.cxx and removed
> > > everything in the write case ( the "else {" part of "if read == 1)").
> > > I get the following output:
> > > bash.exe-2.02$ Event 100 0 0 20
> > > TFile** Event.root
> > > TFile* Event.root
> > > KEY: TH1F htime;1 Real-Time to write versus time
> > > KEY: TTree T;1 An example of a ROOT tree
> > > KEY: TH1F hstat;1 Event Histogram
> > > Error in <TKey::ReadObj>: Unknown class TTree
> > >
> > > What is going on? How can TKey not know about TTrees?
> > > Reading the tree works fine with the unmodified MainEvent.cxx routine.
> That
> > > is puzzling, because I only removed parts that don't get called.
> > >
> > > I am running on Windows NT with ROOT 2.23/11.
> > >
> > > Thanks for any help,
> > >
> > > Reinhard
> >
>
>
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