diff -u -r1.11 -r1.12
--- LCRTRelations.h	21 Jan 2010 16:26:11 -0000	1.11
+++ LCRTRelations.h	5 Oct 2010 16:04:44 -0000	1.12
@@ -242,10 +242,11 @@

 
   /** Special Extension that allows to write int extensions directly (not through a pointer !). */
   template <class U >

-  struct LCIntExtension{  // FIXME: need to check on 64 bit architecture...
-    
-    typedef int ptr ;  // base pointer type 

+  struct LCIntExtension{  

+    typedef long ptr ;  // base pointer type - use long to work for 64 bit (long is 32 on 32-bit systems/64 on 64bit systems)
+    typedef long& ext_type ;                
+

     typedef U tag ;     // this ensures that a new class instance is created for every user extension
     
     static const int allowed_to_call_ext = 1 ;

@@ -257,25 +258,31 @@

     }
     static DeleteFPtr deletePtr() { return  &clean ; }  ;
 

-    typedef int& ext_type ;                

   };
 
 

-  /** Special Extension that allows to write float extensions directly (not through a pointer !). */
-  template <class U >

+  template <class U >
+  

   struct LCFloatExtension{// FIXME: need to check on 64 bit architecture...
 

+#ifdef  __i386__

     typedef float  ptr ;  // base pointer type 

-    typedef U tag ;     // this ensures that a new class instance is created for every user extension

     typedef float& ext_type ;     // return value of  ext<>()

-  

+
+#else  // use double on 64bit systems
+    typedef double  ptr ;  // base pointer type 
+    typedef double& ext_type ;     // return value of  ext<>()
+#endif    
+
+    typedef U tag ;     // this ensures that a new class instance is created for every user extension
+

     static const int allowed_to_call_ext = 1 ;
     static void clean(void *v) { }
     static ptr init() { return 0 ; }
     static DeleteFPtr deletePtr() { return  &clean ; }  ;
   };

-

+  

 
   //--------------------------------------------------------------------
 

diff -u -r1.6 -r1.7
--- lcrtrelation.cc	8 Dec 2006 14:28:59 -0000	1.6
+++ lcrtrelation.cc	5 Oct 2010 16:04:44 -0000	1.7
@@ -18,6 +18,9 @@

 // a simple int extension 
 struct Index : LCIntExtension<Index> {} ;
 

+// a simple float extension 
+struct Mass : LCFloatExtension<Mass> {} ;
+

 // a vector of strings (pointers) that are owned by the object that is extended 
 struct ParticleIDs : LCOwnedExtensionVector<ParticleIDs,std::string> {};
 

@@ -75,6 +78,7 @@

       // make every particle know it's index in the collection 
       mcp->ext<Index>() = i ;   
 

+      mcp->ext<Mass>() = mcp->getMass() ;

 
       // assign a user object to each particle:
 

@@ -301,7 +305,7 @@

 	
 	MCParticle*  mcp = dynamic_cast<MCParticle*>( mcpcol->getElementAt(i) ) ;
 

-	std::cout <<  "   --- particle " << mcp->ext<Index>()   

+	std::cout <<  "   --- particle " << mcp->ext<Index>()  << " ( mass: " << mcp->ext<Mass>() << ") "

 		  <<  " daughters after merging : " ;