diff --git a/Source/Tools/GapiCodegen/CallbackGen.cs b/Source/Tools/GapiCodegen/CallbackGen.cs
index f7554be06..df733b6f2 100644
--- a/Source/Tools/GapiCodegen/CallbackGen.cs
+++ b/Source/Tools/GapiCodegen/CallbackGen.cs
@@ -208,7 +208,7 @@ namespace GtkSharp.Generation {
 			sw.WriteLine ("\tusing System.Runtime.InteropServices;");
 			sw.WriteLine ();
 			sw.WriteLine ("#region Autogenerated code");
-			sw.WriteLine ("\t[UnmanagedFunctionPointer (CallingConvention.Cdecl)]");
+			//sw.WriteLine ("\t[UnmanagedFunctionPointer (CallingConvention.Cdecl)]");
 			sw.WriteLine ("\tinternal delegate " + retval.MarshalType + " " + wrapper + "(" + parms.ImportSignature + ");");
 			sw.WriteLine ();
 			GenInvoker (gen_info, sw);
diff --git a/Source/Tools/GapiCodegen/Ctor.cs b/Source/Tools/GapiCodegen/Ctor.cs
index 0736ce8d1..9a2653b6f 100644
--- a/Source/Tools/GapiCodegen/Ctor.cs
+++ b/Source/Tools/GapiCodegen/Ctor.cs
@@ -65,7 +65,8 @@ namespace GtkSharp.Generation {
 
 		void GenerateImport (StreamWriter sw)
 		{
-			sw.WriteLine("\t\tdelegate IntPtr d_{0}({1});", CName, Parameters.ImportSignature);
+            sw.WriteLine("\t\t[UnmanagedFunctionPointer (CallingConvention.Cdecl)]");
+            sw.WriteLine("\t\tdelegate IntPtr d_{0}({1});", CName, Parameters.ImportSignature);
             sw.WriteLine("\t\tstatic d_{0} {0} = FuncLoader.LoadFunction<d_{0}>(FuncLoader.GetProcAddress(GLibrary.Load(\"{1}\"), \"{0}\"));", CName, LibraryName);
             sw.WriteLine();
 		}
diff --git a/Source/Tools/GapiCodegen/EnumGen.cs b/Source/Tools/GapiCodegen/EnumGen.cs
index 43f360fcd..1db901b89 100644
--- a/Source/Tools/GapiCodegen/EnumGen.cs
+++ b/Source/Tools/GapiCodegen/EnumGen.cs
@@ -19,6 +19,8 @@
 // Boston, MA 02111-1307, USA.
 
 
+using System.Runtime.InteropServices;
+
 namespace GtkSharp.Generation {
 
 	using System;
@@ -113,11 +115,11 @@ namespace GtkSharp.Generation {
 				sw.WriteLine (member);
 
 			sw.WriteLine ("\t}");
-
 			if (Elem.HasAttribute ("gtype")) {
 				sw.WriteLine ();
 				sw.WriteLine ("\tinternal class " + Name + "GType {");
                 var funcname = Elem.GetAttribute("gtype");
+                sw.WriteLine ("\t\t[UnmanagedFunctionPointer (CallingConvention.Cdecl)]");
                 sw.WriteLine ("\t\tdelegate IntPtr d_" + funcname + "();");
 				sw.WriteLine ("\t\tstatic d_" + funcname + " " + funcname + " = FuncLoader.LoadFunction<d_" + funcname + ">(FuncLoader.GetProcAddress(GLibrary.Load(\"" + LibraryName + "\"), \"" + funcname + "\"));");
 				sw.WriteLine ();
diff --git a/Source/Tools/GapiCodegen/Method.cs b/Source/Tools/GapiCodegen/Method.cs
index e2b8f8f9d..e37e0c0dd 100644
--- a/Source/Tools/GapiCodegen/Method.cs
+++ b/Source/Tools/GapiCodegen/Method.cs
@@ -192,7 +192,9 @@ namespace GtkSharp.Generation {
 			import_sig += !IsStatic && Parameters.Count > 0 ? ", " : "";
 			import_sig += Parameters.ImportSignature.ToString();
 
-			if (retval.MarshalType.StartsWith("[return:"))
+            sw.WriteLine("\t\t[UnmanagedFunctionPointer (CallingConvention.Cdecl)]");
+
+            if (retval.MarshalType.StartsWith("[return:"))
 				sw.WriteLine("\t\tdelegate " + retval.CSType + " d_" + CName + "(" + import_sig + ");");
 			else
                 sw.WriteLine("\t\tdelegate " + retval.MarshalType + " d_" + CName + "(" + import_sig + ");");
diff --git a/Source/Tools/Tools.sln b/Source/Tools/Tools.sln
index dde388998..2393795fe 100644
--- a/Source/Tools/Tools.sln
+++ b/Source/Tools/Tools.sln
@@ -1,11 +1,10 @@
-
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.26124.0
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.29306.81
 MinimumVisualStudioVersion = 15.0.26124.0
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GapiCodegen", "GapiCodegen\GapiCodegen.csproj", "{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "GapiCodegen", "GapiCodegen\GapiCodegen.csproj", "{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GapiFixup", "GapiFixup\GapiFixup.csproj", "{DC7A0B5F-448F-4978-849B-3038D9B9C285}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "GapiFixup", "GapiFixup\GapiFixup.csproj", "{DC7A0B5F-448F-4978-849B-3038D9B9C285}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -16,33 +15,36 @@ Global
 		Release|x64 = Release|x64
 		Release|x86 = Release|x86
 	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x64.ActiveCfg = Debug|x64
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x64.Build.0 = Debug|x64
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x86.ActiveCfg = Debug|x86
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x86.Build.0 = Debug|x86
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x64.Build.0 = Debug|Any CPU
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Debug|x86.Build.0 = Debug|Any CPU
 		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|Any CPU.Build.0 = Release|Any CPU
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x64.ActiveCfg = Release|x64
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x64.Build.0 = Release|x64
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x86.ActiveCfg = Release|x86
-		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x86.Build.0 = Release|x86
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x64.ActiveCfg = Release|Any CPU
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x64.Build.0 = Release|Any CPU
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x86.ActiveCfg = Release|Any CPU
+		{2CA6614A-F064-4136-ABDE-2DFB37E0F12B}.Release|x86.Build.0 = Release|Any CPU
 		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x64.ActiveCfg = Debug|x64
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x64.Build.0 = Debug|x64
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x86.ActiveCfg = Debug|x86
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x86.Build.0 = Debug|x86
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x64.Build.0 = Debug|Any CPU
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Debug|x86.Build.0 = Debug|Any CPU
 		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|Any CPU.Build.0 = Release|Any CPU
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x64.ActiveCfg = Release|x64
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x64.Build.0 = Release|x64
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x86.ActiveCfg = Release|x86
-		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x86.Build.0 = Release|x86
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x64.ActiveCfg = Release|Any CPU
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x64.Build.0 = Release|Any CPU
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x86.ActiveCfg = Release|Any CPU
+		{DC7A0B5F-448F-4978-849B-3038D9B9C285}.Release|x86.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {35C3162B-E475-42D4-8ACE-5A81617CDDA9}
 	EndGlobalSection
 EndGlobal