games.C:

#ifndef __RUN_GAMES__

void games()
{
   gSystem->Load("libGui");
   Bool_t UNIX = strcmp(gSystem->GetName(), "Unix") == 0;
   Int_t st1 = gSystem->Load("$(ROOTSYS)/test/Aclock");
   if (st1 == -1) {
      printf("===>The macro games will try to build the Aclock library\n");
      if (UNIX)
         gSystem->Exec("(cd $ROOTSYS/test; make Aclock)");
      else
         gSystem->Exec("(cd %ROOTSYS%\\test && nmake -f Makefile.win32 Aclock.dll)");

      st1 = gSystem->Load("$(ROOTSYS)/test/Aclock");
   }
   Int_t st2 = gSystem->Load("$(ROOTSYS)/test/Hello");
   if (st2 == -1) {
      printf("===>The macro games will try to build the Hello library\n");
      if (UNIX)
         gSystem->Exec("(cd $ROOTSYS/test; make Hello)");
      else
         gSystem->Exec("(cd %ROOTSYS%\\test && nmake -f Makefile.win32 Hello.dll)");

      st2 = gSystem->Load("$(ROOTSYS)/test/Hello");
   }
   Int_t st3 = gSystem->Load("$(ROOTSYS)/test/Tetris");
   if (st3 == -1) {
      if (UNIX) {
         printf("===>The macro games will try to build the Tetris library\n");
         gSystem->Exec("(cd $ROOTSYS/test; make Tetris)");
      } else {
         gSystem->Exec("(cd %ROOTSYS%\\test && nmake -f Makefile.win32 Tetris.dll)");
      }
      st3 = gSystem->Load("$(ROOTSYS)/test/Tetris");
   }
   if (st1 || st2 || st3) {
      printf("ERROR: one of the shared libs in $ROOTSYS/test didn't load properly\n");
      return;
   }
   gROOT->ProcessLine("#define __RUN_GAMES__ 1");
   gROOT->ProcessLine("#include \"games.C\"");
   gROOT->ProcessLine("rungames()");
   gROOT->ProcessLine("#undef __RUN_GAMES__");
}

#else

class Hello;
class Aclock;
class Tetris;

void rungames()
{
   // This macro runs three "games" that each nicely illustrate the graphics capabilities of ROOT.
   // Thanks to the clever usage of TTimer objects it looks like they are all
   // executing in parallel (emulation of multi-threading).
   // It uses the small classes generated in $ROOTSYS/test/Hello,
   // Aclock, Tetris
   //Author: Valeriy Onuchin

   // run the dancing Hello World
   Hello *hello = new Hello();

   // run the analog clock
   Aclock *clock = new Aclock();

   // run the Tetris game
   Tetris *tetris = new Tetris();
}

#endif