diff --git a/Area.h b/Area.h
index add4dcd..de98240 100644
--- a/Area.h
+++ b/Area.h
@@ -60,7 +60,7 @@ class CArea
 	void Offset(double inwards_value);
 	void Thicken(double value);
 	void FitArcs();
-	unsigned int num_curves(){return m_curves.size();}
+	size_t num_curves(){return m_curves.size();}
 	Point NearestPoint(const Point& p)const;
 	void GetBox(CBox2D &box);
 	void Reorder();
diff --git a/AreaClipper.cpp b/AreaClipper.cpp
index 6087078..5030216 100644
--- a/AreaClipper.cpp
+++ b/AreaClipper.cpp
@@ -169,7 +169,7 @@ static void OffsetWithLoops(const TPolyPolygon &pp, TPolyPolygon &pp_new, double
 		{
 			if(reverse)
 			{
-				for(unsigned int j = p.size()-1; j > 1; j--)MakeLoop(p[j], p[j-1], p[j-2], radius);
+				for(size_t j = p.size()-1; j > 1; j--)MakeLoop(p[j], p[j-1], p[j-2], radius);
 				MakeLoop(p[1], p[0], p[p.size()-1], radius);
 				MakeLoop(p[0], p[p.size()-1], p[p.size()-2], radius);
 			}
@@ -213,7 +213,7 @@ static void OffsetWithLoops(const TPolyPolygon &pp, TPolyPolygon &pp_new, double
 			const TPolygon& p = copy[i];
 			TPolygon p_new;
 			p_new.resize(p.size());
-			int size_minus_one = p.size() - 1;
+			size_t size_minus_one = p.size() - 1;
 			for(unsigned int j = 0; j < p.size(); j++)p_new[j] = p[size_minus_one - j];
 			pp_new[i] = p_new;
 		}
@@ -290,7 +290,7 @@ static void OffsetSpansWithObrounds(const CArea& area, TPolyPolygon &pp_new, dou
 		const TPolygon& p = copy[i];
 		TPolygon p_new;
 		p_new.resize(p.size());
-		int size_minus_one = p.size() - 1;
+		size_t size_minus_one = p.size() - 1;
 		for(unsigned int j = 0; j < p.size(); j++)p_new[j] = p[size_minus_one - j];
 		pp_new[i] = p_new;
 	}
@@ -315,7 +315,7 @@ static void MakePolyPoly( const CArea& area, TPolyPolygon &pp, bool reverse = tr
 		p.resize(pts_for_AddVertex.size());
 		if(reverse)
 		{
-			unsigned int i = pts_for_AddVertex.size() - 1;// clipper wants them the opposite way to CArea
+			size_t i = pts_for_AddVertex.size() - 1;// clipper wants them the opposite way to CArea
 			for(std::list<DoubleAreaPoint>::iterator It = pts_for_AddVertex.begin(); It != pts_for_AddVertex.end(); It++, i--)
 			{
 				p[i] = It->int_point();
diff --git a/kurve/Finite.cpp b/kurve/Finite.cpp
index cb53c01..fedbfd5 100644
--- a/kurve/Finite.cpp
+++ b/kurve/Finite.cpp
@@ -9,7 +9,7 @@
 //            finite intersections
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-#ifndef WIN32
+#ifndef _WIN32
 #define __min(a,b) ((a<b)?a:b)
 #define __max(a,b) ((a>b)?a:b)
 #endif