diff --git a/src/ifcgeom_schema_agnostic/IteratorImplementation.cpp b/src/ifcgeom_schema_agnostic/IteratorImplementation.cpp
index 2333ade00f..ad94ad063c 100644
--- a/src/ifcgeom_schema_agnostic/IteratorImplementation.cpp
+++ b/src/ifcgeom_schema_agnostic/IteratorImplementation.cpp
@@ -8,13 +8,13 @@
 // - extern void init_IteratorImplementation_Ifc2x3(IteratorFactoryImplementation*);
 // - ...
 #define EXTERNAL_DEFS(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(extern void init_IteratorImplementation_, elem), (IteratorFactoryImplementation*);)
+	extern void BOOST_PP_CAT(init_IteratorImplementation_, elem)(IteratorFactoryImplementation*);
 
 // Declares the schema-based external iterator initialization routines:
 // - init_IteratorImplementation_Ifc2x3(this);
 // - ...
 #define CALL_DEFS(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(init_IteratorImplementation_, elem), (this);)
+	BOOST_PP_CAT(init_IteratorImplementation_, elem)(this);
 
 IFC_GEOM_API IteratorFactoryImplementation& iterator_implementations() {
 	static IteratorFactoryImplementation impl;
diff --git a/src/ifcgeom_schema_agnostic/Kernel.cpp b/src/ifcgeom_schema_agnostic/Kernel.cpp
index fdea7a5d75..4eeb0bf874 100644
--- a/src/ifcgeom_schema_agnostic/Kernel.cpp
+++ b/src/ifcgeom_schema_agnostic/Kernel.cpp
@@ -55,13 +55,13 @@ IfcGeom::impl::KernelFactoryImplementation& IfcGeom::impl::kernel_implementation
 // - extern void init_KernelImplementation_Ifc2x3(IfcGeom::impl::KernelFactoryImplementation*);
 // - ...
 #define EXTERNAL_DEFS(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(extern void init_KernelImplementation_, elem), (IfcGeom::impl::KernelFactoryImplementation*);)
+	extern void BOOST_PP_CAT(init_KernelImplementation_, elem)(IfcGeom::impl::KernelFactoryImplementation*);
 
 // Declares the schema-based external iterator initialization routines:
 // - init_IteratorImplementation_Ifc2x3(this);
 // - ...
 #define CALL_DEFS(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(init_KernelImplementation_, elem), (this);)
+	BOOST_PP_CAT(init_KernelImplementation_, elem)(this);
 
 BOOST_PP_SEQ_FOR_EACH(EXTERNAL_DEFS, , SCHEMA_SEQ)
 
diff --git a/src/ifcgeom_schema_agnostic/Serialization.cpp b/src/ifcgeom_schema_agnostic/Serialization.cpp
index 522b3eace8..e3eea14db8 100644
--- a/src/ifcgeom_schema_agnostic/Serialization.cpp
+++ b/src/ifcgeom_schema_agnostic/Serialization.cpp
@@ -7,10 +7,10 @@
 #include <boost/algorithm/string/case_conv.hpp>
 
 #define EXTERNAL_DEFS_1(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(IfcUtil::IfcBaseClass* tesselate_, elem), (const TopoDS_Shape& shape, double deflection);)
+	IfcUtil::IfcBaseClass* BOOST_PP_CAT(tesselate_, elem)(const TopoDS_Shape& shape, double deflection);
 
 #define EXTERNAL_DEFS_2(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(IfcUtil::IfcBaseClass* serialise_, elem), (const TopoDS_Shape& shape, bool advanced);)
+	IfcUtil::IfcBaseClass* BOOST_PP_CAT(serialise_, elem)(const TopoDS_Shape& shape, bool advanced);
 
 #define CONDITIONAL_CALL(r, data, elem) \
 	if (schema_name_lower == BOOST_PP_STRINGIZE(BOOST_PP_CAT(elem,))) { \
diff --git a/src/serializers/XmlSerializer.cpp b/src/serializers/XmlSerializer.cpp
index 81386fb33e..25ac9b8aeb 100644
--- a/src/serializers/XmlSerializer.cpp
+++ b/src/serializers/XmlSerializer.cpp
@@ -5,10 +5,10 @@
 #include <boost/algorithm/string/case_conv.hpp>
 
 #define EXTERNAL_DEFS(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(extern void init_XmlSerializer, elem), (XmlSerializerFactory::Factory*);)
+	extern void BOOST_PP_CAT(init_XmlSerializer, elem)(XmlSerializerFactory::Factory*);
 
 #define CALL_DEFS(r, data, elem) \
-	BOOST_PP_CAT(BOOST_PP_CAT(init_XmlSerializer, elem), (this);)
+	BOOST_PP_CAT(init_XmlSerializer, elem)(this);
 
 BOOST_PP_SEQ_FOR_EACH(EXTERNAL_DEFS, , SCHEMA_SEQ)