From 15f4f38e48470f5f0b1ba7f42a725e8d9af869f4 Mon Sep 17 00:00:00 2001
From: Christian Zimmermann <christian.zimmermann@ur.de>
Date: Sun, 29 Jul 2018 14:35:53 +0200
Subject: [PATCH] fix null range instace issue

---
 src/lib/ranges/range_types/null_range.cc | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/lib/ranges/range_types/null_range.cc b/src/lib/ranges/range_types/null_range.cc
index 5398e8f..f19251b 100644
--- a/src/lib/ranges/range_types/null_range.cc
+++ b/src/lib/ranges/range_types/null_range.cc
@@ -13,27 +13,31 @@ namespace MultiArrayTools
      *   SingleRange    *
      ********************/
 
+    std::shared_ptr<SingleRange<size_t,SpaceType::NUL>>
+    SingleRangeFactory<size_t,SpaceType::NUL>::mRInstance = nullptr;
+    
     std::shared_ptr<NullRange> nullr()
     {
-	return SingleRangeFactory<size_t,SpaceType::NUL>::mRInstance;
+	static NullRF nrf; // just that mRInstance is initialized
+	static auto nr = std::dynamic_pointer_cast<NullRange>( nrf.create() );
+	VCHECK(NullRF::mRInstance);
+	return NullRF::mRInstance;
     }
 
     std::shared_ptr<NullIndex> nulli()
     {
 	return std::make_shared<NullIndex>(nullr());
     }
-    
-    std::shared_ptr<SingleRange<size_t,SpaceType::NUL>>
-    SingleRangeFactory<size_t,SpaceType::NUL>::mRInstance = nullptr;
 
     SingleRangeFactory<size_t,SpaceType::NUL>::SingleRangeFactory()
     {
 	// Singleton
-	if( not mRInstance){
+	if(not mRInstance){
 	    if(not mProd){
 		mProd = std::shared_ptr<oType>( new SingleRange<size_t,SpaceType::NUL>() );
 		setSelf();
 	    }
+	    mRInstance = std::dynamic_pointer_cast<NullRange>( mProd );
 	} else {
 	    mProd = mRInstance;
 	}