Re: Displaying graphs before main() returns

From: Rene Brun <>
Date: Wed, 31 May 2006 13:02:36 +0200

Hi Roland,

Could you clarify what you mean by
 "My experience goes exactly in the opposite direction"?

The main program syndrom

Of course, nobody prevents you to write your own main program. This is necessary when you implement your own event loop. By event loop, I mean graphics/system event loop.

It is much better to execute a script (interpreted or compiled) from the ROOT prompt. This script can load automatically one or more shared libs (plug-ins). Making plug-ins makes your program more modular. It also greatly facilitates our job. In particular, we see many reports where people do not understand what is an event loop. They forget to instantiate a TApplication (or TRint) object. They forget to send the makefile to build the executable, etc.

Rene Brun

Roland Kuhn wrote:
> Hi Rene!
> On 30 May 2006, at 08:37, Rene Brun wrote:
>> If you create your own executable (with a main) and this application
>> has graphics,
>> you must create a TApplication object. See example in
>> $ROOTSYS/test/hworld.cxx
>> It is in general a very bad idea to create your own main program. You
>> better execute scripts
>> from the ROOT prompt.
> Could you elaborate on this? My experience goes exactly in the
> opposite direction.
> Ciao,
> Roland
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Received on Wed May 31 2006 - 13:02:43 MEST

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