diff --git a/montecarlo/vmc/inc/TMCtls.h b/montecarlo/vmc/inc/TMCtls.h
new file mode 100644
index 0000000000000000000000000000000000000000..95fea95a98b92f7ed2bf563f229450a5d11c8b25
--- /dev/null
+++ b/montecarlo/vmc/inc/TMCtls.h
@@ -0,0 +1,62 @@
+// @(#)root/vmc:$Id$
+// Author: Ivana Hrivnacova, 29/04/2014
+
+/*************************************************************************
+ * Copyright (C) 2014, Rene Brun and Fons Rademakers. *
+ * All rights reserved. *
+ * *
+ * For the licensing terms see $ROOTSYS/LICENSE. *
+ * For the list of contributors see $ROOTSYS/README/CREDITS. *
+ *************************************************************************/
+
+// ********************************************************************
+// * License and Disclaimer *
+// * *
+// * The Geant4 software is copyright of the Copyright Holders of *
+// * the Geant4 Collaboration. It is provided under the terms and *
+// * conditions of the Geant4 Software License, included in the file *
+// * LICENSE and available at http://cern.ch/geant4/license . These *
+// * include a list of copyright holders. *
+// * *
+// * Neither the authors of this software system, nor their employing *
+// * institutes,nor the agencies providing financial support for this *
+// * work make any representation or warranty, express or implied, *
+// * regarding this software system or assume any liability for its *
+// * use. Please see the license in the file LICENSE and URL above *
+// * for the full disclaimer and the limitation of liability. *
+// * *
+// * This code implementation is the result of the scientific and *
+// * technical work of the GEANT4 collaboration. *
+// * By using, copying, modifying or distributing the software (or *
+// * any work based on the software) you agree to acknowledge its *
+// * use in resulting scientific publications, and indicate your *
+// * acceptance of all terms of the Geant4 Software license. *
+// ********************************************************************
+
+#ifndef ROOT_TMCtls
+#define ROOT_TMCtls
+
+// Thread Local Storage typedefs
+//
+// According to Geant4 tls.hh and G4Threading.hh
+
+// Always build with thread support but keep a possibility to introduce
+// a build option
+#define VMC_MULTITHREADED 1
+
+#if ( defined (VMC_MULTITHREADED) )
+ #if ( ( defined(__MACH__) && defined(__clang__) && defined(__x86_64__) ) || \
+ ( defined(__MACH__) && defined(__GNUC__) && __GNUC__>=4 && __GNUC_MINOR__>=7 ) || \
+ defined(__linux__) || defined(_AIX) ) && ( !defined(__CINT__) )
+ // Multi-threaded build: for POSIX systems
+ #include <pthread.h>
+ #define TMCThreadLocal __thread
+ #else
+ //# error "No Thread Local Storage (TLS) technology supported for this platform. Use sequential build !"
+ #define TMCThreadLocal
+ #endif
+#else
+ #define TMCThreadLocal
+#endif
+
+#endif //ROOT_TMCtls
diff --git a/montecarlo/vmc/inc/TVirtualMC.h b/montecarlo/vmc/inc/TVirtualMC.h
index 0abf72c157ef11efd3b4d2c0fb992282c3b843cf..8df57cb8f0105d623ecd463dc98e075847c180d4 100644
--- a/montecarlo/vmc/inc/TVirtualMC.h
+++ b/montecarlo/vmc/inc/TVirtualMC.h
@@ -24,6 +24,7 @@
#include "TMCProcess.h"
#include "TMCParticleType.h"
#include "TMCOptical.h"
+#include "TMCtls.h"
#include "TVirtualMCApplication.h"
#include "TVirtualMCStack.h"
#include "TVirtualMCDecayer.h"
@@ -32,10 +33,6 @@
#include "TString.h"
#include "TError.h"
-#if defined(__linux__) && !defined(__CINT__)
-#include <pthread.h>
-#endif
-
class TLorentzVector;
class TGeoHMatrix;
class TArrayI;
@@ -866,10 +863,10 @@ private:
TVirtualMC(const TVirtualMC &mc);
TVirtualMC & operator=(const TVirtualMC &);
-#if defined(__linux__) && !defined(__CINT__)
- static __thread TVirtualMC* fgMC; // Monte Carlo singleton instance
+#if !defined(__CINT__)
+ static TMCThreadLocal TVirtualMC* fgMC; // Monte Carlo singleton instance
#else
- static TVirtualMC* fgMC; // Monte Carlo singleton instance
+ static TVirtualMC* fgMC; // Monte Carlo singleton instance
#endif
TVirtualMCStack* fStack; //! Particles stack
@@ -880,10 +877,10 @@ private:
ClassDef(TVirtualMC,1) //Interface to Monte Carlo
};
-#if defined(__linux__) && !defined(__CINT__)
-R__EXTERN __thread TVirtualMC *gMC;
+#if !defined(__CINT__)
+R__EXTERN TMCThreadLocal TVirtualMC *gMC;
#else
-R__EXTERN TVirtualMC *gMC;
+R__EXTERN TVirtualMC *gMC;
#endif
#endif //ROOT_TVirtualMC
diff --git a/montecarlo/vmc/inc/TVirtualMCApplication.h b/montecarlo/vmc/inc/TVirtualMCApplication.h
index cb1727400e6eb6ecfeb167e6a0fc61a2fe541516..07594afb6893cda5e8a5b8979004f3a2bd16f75a 100644
--- a/montecarlo/vmc/inc/TVirtualMCApplication.h
+++ b/montecarlo/vmc/inc/TVirtualMCApplication.h
@@ -25,9 +25,7 @@
#include "TMath.h"
#endif
-#if defined(__linux__) && !defined(__CINT__)
-#include <pthread.h>
-#endif
+#include "TMCtls.h"
class TVirtualMCApplication : public TNamed {
@@ -112,10 +110,10 @@ public:
private:
// static data members
-#if defined(__linux__) && !defined(__CINT__)
- static __thread TVirtualMCApplication* fgInstance; // singleton instance
+#if !defined(__CINT__)
+ static TMCThreadLocal TVirtualMCApplication* fgInstance; // singleton instance
#else
- static TVirtualMCApplication* fgInstance; // singleton instance
+ static TVirtualMCApplication* fgInstance; // singleton instance
#endif
ClassDef(TVirtualMCApplication,1) //Interface to MonteCarlo application
diff --git a/montecarlo/vmc/src/TVirtualMC.cxx b/montecarlo/vmc/src/TVirtualMC.cxx
index b0bbbebec757f15eca26a464f48fca5014a3c38e..678427a8d4426988e67d263b65d2bfb0a7870740 100644
--- a/montecarlo/vmc/src/TVirtualMC.cxx
+++ b/montecarlo/vmc/src/TVirtualMC.cxx
@@ -26,13 +26,8 @@
ClassImp(TVirtualMC)
-#if defined(__linux__) && !defined(__CINT__)
-__thread TVirtualMC* TVirtualMC::fgMC=0;
-__thread TVirtualMC* gMC;
-#else
-TVirtualMC* TVirtualMC::fgMC=0;
-TVirtualMC* gMC;
-#endif
+TMCThreadLocal TVirtualMC* TVirtualMC::fgMC=0;
+TMCThreadLocal TVirtualMC* gMC;
//_____________________________________________________________________________
TVirtualMC::TVirtualMC(const char *name, const char *title,
diff --git a/montecarlo/vmc/src/TVirtualMCApplication.cxx b/montecarlo/vmc/src/TVirtualMCApplication.cxx
index 0556c06dd07eb234501d090a7cbaffcca1b8042a..003392b0f6f7eab5f71241fdbc83e702c293fa07 100644
--- a/montecarlo/vmc/src/TVirtualMCApplication.cxx
+++ b/montecarlo/vmc/src/TVirtualMCApplication.cxx
@@ -20,11 +20,7 @@
ClassImp(TVirtualMCApplication)
-#if defined(__linux__) && !defined(__CINT__)
-__thread TVirtualMCApplication* TVirtualMCApplication::fgInstance = 0;
-#else
-TVirtualMCApplication* TVirtualMCApplication::fgInstance = 0;
-#endif
+TMCThreadLocal TVirtualMCApplication* TVirtualMCApplication::fgInstance = 0;
//_____________________________________________________________________________
TVirtualMCApplication::TVirtualMCApplication(const char *name,