diff --git a/include/core_api/light.h b/include/core_api/light.h
index a179890e..4509b841 100755
--- a/include/core_api/light.h
+++ b/include/core_api/light.h
@@ -7,7 +7,7 @@
 
 __BEGIN_YAFRAY
 
-struct surfacePoint_t;
+class surfacePoint_t;
 class background_t;
 
 enum { LIGHT_NONE = 0, LIGHT_DIRACDIR = 1, LIGHT_SINGULAR = 1<<1 }; // "LIGHT_DIRACDIR" *must* be same as "BSDF_SPECULAR" (material.h)!
diff --git a/include/core_api/material.h b/include/core_api/material.h
index 533fcff6..5f28498b 100755
--- a/include/core_api/material.h
+++ b/include/core_api/material.h
@@ -25,7 +25,7 @@ class YAFRAYCORE_EXPORT BSDF_t
 };
 */
 
-struct surfacePoint_t;
+class surfacePoint_t;
 struct renderState_t;
 class volumeHandler_t;
 
diff --git a/include/core_api/object3d.h b/include/core_api/object3d.h
index 4737f50f..5f4a1d07 100755
--- a/include/core_api/object3d.h
+++ b/include/core_api/object3d.h
@@ -15,7 +15,7 @@ __BEGIN_YAFRAY
 
 class light_t;
 class primitive_t;
-struct surfacePoint_t;
+class surfacePoint_t;
 
 class YAFRAYCORE_EXPORT object3d_t
 {
diff --git a/include/core_api/tiledintegrator.h b/include/core_api/tiledintegrator.h
index 5e9c23bb..b7d3c3ab 100755
--- a/include/core_api/tiledintegrator.h
+++ b/include/core_api/tiledintegrator.h
@@ -8,7 +8,15 @@
 
 __BEGIN_YAFRAY
 
-class threadControl_t;
+class threadControl_t
+{
+	public:
+		threadControl_t() : finishedThreads(0) {}
+		std::mutex m;
+		std::condition_variable c; //!< condition variable to signal main thread
+		std::vector<renderArea_t> areas; //!< area to be output to e.g. blender, if any
+		volatile int finishedThreads; //!< number of finished threads, lock countCV when increasing/reading!
+};
 
 class YAFRAYCORE_EXPORT tiledIntegrator_t: public surfaceIntegrator_t
 {
@@ -56,15 +64,6 @@ class YAFRAYCORE_EXPORT tiledIntegrator_t: public surfaceIntegrator_t
 		static std::vector<int> correlativeSampleNumber;  //!< Used to sample lights more uniformly when using estimateOneDirectLight
 };
 
-struct threadControl_t
-{
-	threadControl_t() : finishedThreads(0) {}
-	std::mutex m;
-	std::condition_variable c; //!< condition variable to signal main thread
-	std::vector<renderArea_t> areas; //!< area to be output to e.g. blender, if any
-	volatile int finishedThreads; //!< number of finished threads, lock countCV when increasing/reading!
-};
-
 __END_YAFRAY
 
 #endif // Y_TILEDINTEGRATOR_H