diff --git a/src/lib_json/json_reader.cpp b/src/lib_json/json_reader.cpp
index 5e04d74..d5ff46d 100644
--- a/src/lib_json/json_reader.cpp
+++ b/src/lib_json/json_reader.cpp
@@ -45,7 +45,11 @@
 #endif
 
 static int const stackLimit_g = 1000;
+#if __cplusplus >= 201103L
+thread_local static int stackDepth_g = 0;  // see readValue()
+#else
 static int       stackDepth_g = 0;  // see readValue()
+#endif
 
 namespace Json {