Re: [ROOT] weird behavior with TUnixSystem

From: Glen R. Salo (gsalo@mrcstl.com)
Date: Mon Jul 02 2001 - 18:56:16 MEST


Fons:

>From the documentation, it was not clear to me that I should not use
TUnixSystem.  I will now use the global pointer gSystem instead.  My
example did not need to use TUnixSystem; rather, I used it to demonstrate
the problem I was having using TUnixSystem in my "real" code.  Thanks for
you help.

Glen



On 02-Jul-2001 Fons Rademakers wrote:
> Hi Glen,
> 
>    never create a TUnixSystem object yourself (why was your intention)?
> Anyway, the following version of your viewer.cxx works fine:
> 
> //==================================
>#include <TApplication.h>
>#include <TTree.h>
>#include <TFile.h>
> 
> class TViewer {
> 
>  private:
>   TTree *fTree;
>   TFile *fFile;
> 
>  public:
>   TViewer() {
>     fFile = new TFile("tree3.root");
>     fTree = (TTree *)fFile->Get("t3");
>     fTree->StartViewer();
>   }
>   ~TViewer() {delete fFile;}
> };
> 
> void main(int argc, char **argv) {
> 
>   TApplication theApp("test",&argc,argv);
>   new TViewer();
>   theApp.Run();
> }
> //==================================
> 
> 
> Cheers, Fons.
> 
> 
> 
> 
> "Glen R. Salo" wrote:
>> 
>> I am having strange problems when I use TUnixSystem as illustrated in
>> the
>> attached code.  Compile the code (g++ -o viewer viewer.cxx `root-config
>> --cflags` `root-config --libs`), copy tree3.root from tutorials to the
>> same directory, and run viewer.  On my computer, if I draw "ntrack" a
>> histogram is drawn correctly.  However, if I try to draw any of the
>> other
>> branches ("stat", "sign", ...), the code immediately exits and writes
>> "Alarm clock" to my shell window.  If the UnixSystem line is removed or
>> replaced with "TUnixSystem *System = new TUnixSystem();" the program
>> works
>> fine.
>> 
>> Thanks for your help,
>> 
>> Glen
>> 
>>   ----------------------------------------------------------------------
>>   ----------
>>                     Name: viewer.cxx
>>    viewer.cxx       Type: unspecified type (application/octet-stream)
>>                 Encoding: base64
>>              Description: viewer.cxx
> 
> -- 
> Org:    CERN, European Laboratory for Particle Physics.
> Mail:   1211 Geneve 23, Switzerland
> E-Mail: Fons.Rademakers@cern.ch              Phone: +41 22 7679248
> WWW:    http://root.cern.ch/~rdm/            Fax:   +41 22 7677910



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