diff --git a/libethcore/EthashAux.cpp b/libethcore/EthashAux.cpp
index 51a606ff8..14a44a812 100644
--- a/libethcore/EthashAux.cpp
+++ b/libethcore/EthashAux.cpp
@@ -49,6 +49,13 @@ EthashAux::~EthashAux()
 {
 }
 
+EthashAux* EthashAux::get()
+{
+    static std::once_flag flag;
+    std::call_once(flag, []{s_this = new EthashAux();});
+    return s_this;
+}
+
 uint64_t EthashAux::cacheSize(BlockInfo const& _header)
 {
 	return ethash_get_cachesize((uint64_t)_header.number);
diff --git a/libethcore/EthashAux.h b/libethcore/EthashAux.h
index 47180bfd2..d5bd60d44 100644
--- a/libethcore/EthashAux.h
+++ b/libethcore/EthashAux.h
@@ -38,7 +38,7 @@ class EthashAux
 public:
 	~EthashAux();
 
-	static EthashAux* get() { if (!s_this) s_this = new EthashAux(); return s_this; }
+	static EthashAux* get();
 
 	struct LightAllocation
 	{