From a3bc1593590796abeb89fbc9c304ef6727d5b998 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Sun, 20 Dec 2020 14:38:54 +0100
Subject: [PATCH] #1173 mutex in get_default_style()

---
 src/ifcgeom_schema_agnostic/SurfaceStyle.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/ifcgeom_schema_agnostic/SurfaceStyle.cpp b/src/ifcgeom_schema_agnostic/SurfaceStyle.cpp
index 6760b20a6d..8484d3fb36 100644
--- a/src/ifcgeom_schema_agnostic/SurfaceStyle.cpp
+++ b/src/ifcgeom_schema_agnostic/SurfaceStyle.cpp
@@ -4,6 +4,7 @@
 #include <boost/property_tree/ptree.hpp>
 
 #include <map>
+#include <mutex>
 
 namespace pt = boost::property_tree;
 
@@ -112,6 +113,9 @@ void IfcGeom::set_default_style_file(const std::string& json_file) {
 }
 
 const IfcGeom::SurfaceStyle* IfcGeom::get_default_style(const std::string& s) {
+	static std::mutex m;
+	std::lock_guard<std::mutex> lk(m);
+
 	if (!default_materials_initialized) InitDefaultMaterials();
 	std::map<std::string, IfcGeom::SurfaceStyle>::const_iterator it = default_materials.find(s);
 	if (it == default_materials.end()) {