Reworked support for out parameters in both backends and added a test.

src/Generator/Generators/CLI/CLIMarshal.cs

@@ -45,6 +45,13 @@ namespace CppSharp.Generators.CLI
         {
             var pointee = pointer.Pointee;
 
+            var param = Context.Parameter;
+            if (param != null && (param.IsOut || param.IsInOut))
+            {
+                Context.Return.Write(Context.ReturnVarName);
+                return true;
+            }
+
             if (pointee.Desugar().IsPrimitiveType(PrimitiveType.Void))
             {
                 Context.Return.Write("IntPtr({0})", Context.ReturnVarName);
@@ -234,7 +241,11 @@ namespace CppSharp.Generators.CLI
 
         public override bool VisitParameterDecl(Parameter parameter)
         {
-            return parameter.Type.Visit(this, parameter.QualifiedType.Qualifiers);
+            Context.Parameter = parameter;
+            var ret = parameter.Type.Visit(this, parameter.QualifiedType.Qualifiers);
+            Context.Parameter = null;
+
+            return ret;
         }
 
         public override bool VisitTypedefDecl(TypedefDecl typedef)
@@ -527,7 +538,8 @@ namespace CppSharp.Generators.CLI
 
         public void MarshalValueClass(Class @class)
         {
-            var marshalVar = "_marshal" + Context.ParameterIndex++;
+            var marshalVar = Context.MarshalVarPrefix + "_marshal" +
+                Context.ParameterIndex++;
 
             Context.SupportBefore.WriteLine("auto {0} = ::{1}();", marshalVar,
                 @class.QualifiedOriginalName);
@@ -572,7 +584,8 @@ namespace CppSharp.Generators.CLI
             var marshalCtx = new MarshalContext(Context.Driver)
                                  {
                                      ArgName = fieldRef,
-                                     ParameterIndex = Context.ParameterIndex++
+                                     ParameterIndex = Context.ParameterIndex++,
+                                     MarshalVarPrefix = Context.MarshalVarPrefix
                                  };
 
             var marshal = new CLIMarshalManagedToNativePrinter(marshalCtx);

src/Generator/Generators/CLI/CLISourcesTemplate.cs

@@ -632,12 +632,14 @@ namespace CppSharp.Generators.CLI
         {
             var names = new List<string>();
 
+            var paramIndex = 0;
             foreach (var param in method.Parameters)
             {
                 var ctx = new MarshalContext(Driver)
                               {
                                   Parameter = param,
                                   ArgName = param.Name,
+                                  ParameterIndex = paramIndex++
                               };
 
                 var marshal = new CLIMarshalManagedToNativePrinter(ctx);
@@ -729,7 +731,11 @@ namespace CppSharp.Generators.CLI
                 WriteLine("auto {0} = ::{1}();", valueMarshalName, @class.QualifiedOriginalName);
 
                 var param = new Parameter() { Name = "(*this)" };
-                var ctx = new MarshalContext(Driver) { Parameter = param };
+                var ctx = new MarshalContext(Driver)
+                    {
+                        MarshalVarPrefix = valueMarshalName,
+                        Parameter = param
+                    };
 
                 var marshal = new CLIMarshalManagedToNativePrinter(ctx);
                 marshal.MarshalValueClassFields(@class, valueMarshalName);
@@ -860,6 +866,8 @@ namespace CppSharp.Generators.CLI
         public struct ParamMarshal
         {
             public string Name;
+            public string Prefix;
+
             public Parameter Param;
         } 
 
@@ -881,18 +889,21 @@ namespace CppSharp.Generators.CLI
         private ParamMarshal GenerateFunctionParamMarshal(Parameter param, int paramIndex,
             Function function = null)
         {
+            var paramMarshal = new ParamMarshal { Name = param.Name, Param = param };
+
             if (param.Type is BuiltinType)
-            {
-                return new ParamMarshal {Name = param.Name, Param = param};
-            }
+                return paramMarshal;
 
             var argName = "arg" + paramIndex.ToString(CultureInfo.InvariantCulture);
 
-            if (param.Usage == ParameterUsage.Out)
+            if (param.IsOut || param.IsInOut)
             {
                 var paramType = param.Type;
-                if (paramType.IsReference())
+                if (paramType is PointerType)
+                {
                     paramType = (paramType as PointerType).Pointee;
+                    paramMarshal.Prefix = "&";
+                }
 
                 var typePrinter = new CppTypePrinter(Driver.TypeDatabase);
                 var type = paramType.Visit(typePrinter);
@@ -923,12 +934,18 @@ namespace CppSharp.Generators.CLI
                 argName = marshal.ArgumentPrefix + argName;
             }
 
-            return new ParamMarshal {Name = argName, Param = param};
+            paramMarshal.Name = argName;
+            return paramMarshal;
         }
 
         public void GenerateFunctionParams(List<ParamMarshal> @params)
         {
-            var names = @params.Select(param => param.Name).ToList();
+            var names = @params.Select(param =>
+                {
+                    if (!string.IsNullOrWhiteSpace(param.Prefix))
+                        return param.Prefix + param.Name;
+                    return param.Name;
+                }).ToList();
             Write(string.Join(", ", names));
         }
 

src/Generator/Generators/CLI/CLITypePrinter.cs

@@ -91,10 +91,11 @@ namespace CppSharp.Generators.CLI
 
         public string VisitParameter(Parameter param, bool hasName = true)
         {
+            Context.Parameter = param;
             var type = param.Type.Visit(this, param.QualifiedType.Qualifiers);
-            var name = param.Name;
-            var str = "";
+            Context.Parameter = null;
 
+            var str = string.Empty;
             if(param.Usage == ParameterUsage.Out)
                 str += "[System::Runtime::InteropServices::Out] ";
 
@@ -104,8 +105,8 @@ namespace CppSharp.Generators.CLI
                param.Usage == ParameterUsage.InOut)
                 str += "%";
 
-            if (hasName && !string.IsNullOrEmpty(name))
-                str += " " + name;
+            if (hasName && !string.IsNullOrEmpty(param.Name))
+                str += " " + param.Name;
 
             return str;
         }
@@ -135,6 +136,10 @@ namespace CppSharp.Generators.CLI
             PrimitiveType primitive;
             if (pointee.Desugar().IsPrimitiveType(out primitive))
             {
+                var param = Context.Parameter;
+                if (param != null && (param.IsOut || param.IsInOut))
+                    return VisitPrimitiveType(primitive);
+
                 return "System::IntPtr";
             }
 

src/Generator/Generators/CSharp/CSharpMarshal.cs

@@ -141,6 +141,13 @@ namespace CppSharp.Generators.CSharp
             PrimitiveType primitive;
             if (pointee.Desugar().IsPrimitiveType(out primitive))
             {
+                var param = Context.Parameter;
+                if (param != null && (param.IsOut || param.IsInOut))
+                {
+                    Context.Return.Write("_{0}", param.Name);
+                    return true;
+                }
+
                 Context.Return.Write(Context.ReturnVarName);
                 return true;
             }
@@ -410,7 +417,24 @@ namespace CppSharp.Generators.CSharp
             PrimitiveType primitive;
             if (type.IsPrimitiveType(out primitive))
             {
+                var param = Context.Parameter;
+
+                // From MSDN: "note that a ref or out parameter is classified as a moveable
+                // variable". This means we must create a local variable to hold the result
+                // and then assign this value to the parameter.
+
+                if (param.IsOut || param.IsInOut)
+                {
+                    var typeName = Type.TypePrinterDelegate(type);
+
+                    Context.SupportBefore.WriteLine("{0} _{1};", typeName,
+                        Helpers.SafeIdentifier(param.Name));
+                    Context.Return.Write("new global::System.IntPtr(&_{0})", param.Name);
+
+                }
+                else
                     Context.Return.Write(Context.Parameter.Name);
+
                 return true;
             }
 

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -1813,13 +1813,13 @@ namespace CppSharp.Generators.CSharp
             foreach (var paramInfo in @params)
             {
                 var param = paramInfo.Param;
-                if (param.Usage != ParameterUsage.Out && param.Usage != ParameterUsage.InOut)
-                    continue;
+                if (!(param.IsOut || param.IsInOut)) continue;
 
                 var nativeVarName = paramInfo.Name;
 
                 var ctx = new CSharpMarshalContext(Driver)
                 {
+                    Parameter = param,
                     ArgName = nativeVarName,
                     ReturnVarName = nativeVarName,
                     ReturnType = param.QualifiedType
@@ -1890,7 +1890,7 @@ namespace CppSharp.Generators.CSharp
             var argName = "arg" + paramIndex.ToString(CultureInfo.InvariantCulture);
             var paramMarshal = new ParamMarshal { Name = argName, Param = param };
 
-            if (param.Usage == ParameterUsage.Out)
+            if (param.IsOut || param.IsInOut)
             {
                 var paramType = param.Type;
 
@@ -1949,8 +1949,9 @@ namespace CppSharp.Generators.CSharp
                 if (param.Kind == ParameterKind.IndirectReturnType)
                     continue;
 
+                var typeName = param.CSharpType(TypePrinter);
                 @params.Add(string.Format("{0}{1} {2}", GetParameterUsage(param.Usage),
-                    param.Type, SafeIdentifier(param.Name)));
+                    typeName, SafeIdentifier(param.Name)));
             }
 
             Write(string.Join(", ", @params));

src/Generator/Generators/CSharp/CSharpTypePrinter.cs

@@ -174,7 +174,13 @@ namespace CppSharp.Generators.CSharp
 
             PrimitiveType primitive;
             if (pointee.Desugar().IsPrimitiveType(out primitive))
+            {
+                if (isManagedContext && Context.Parameter != null &&
+                    (Context.Parameter.IsOut || Context.Parameter.IsInOut))
+                    return VisitPrimitiveType(primitive, quals);
+
                 return "global::System.IntPtr";
+            }
 
             Class @class;
             if (pointee.IsTagDecl(out @class)
@@ -365,7 +371,11 @@ namespace CppSharp.Generators.CSharp
             if (parameter.Kind == ParameterKind.IndirectReturnType)
                 return "global::System.IntPtr";
 
-            return paramType.Visit(this);
+            Context.Parameter = parameter;
+            var ret = paramType.Visit(this);
+            Context.Parameter = null;
+
+            return ret;
         }
 
         public CSharpTypePrinterResult VisitTypedefDecl(TypedefDecl typedef)
@@ -439,8 +449,12 @@ namespace CppSharp.Generators.CSharp
             var args = new List<string>();
 
             foreach (var param in @params)
+            {
+                Context.Parameter = param;
                 args.Add(VisitParameter(param, hasNames).Type);
+            }
 
+            Context.Parameter = null;
             return string.Join(", ", args);
         }
 

src/Generator/Generators/Marshal.cs

@@ -9,6 +9,7 @@ namespace CppSharp.Generators
             Driver = driver;
             SupportBefore = new TextGenerator();
             Return = new TextGenerator();
+            MarshalVarPrefix = string.Empty;
         }
 
         public Driver Driver { get; private set; }
@@ -28,6 +29,8 @@ namespace CppSharp.Generators
         public Parameter Parameter { get; set; }
         public int ParameterIndex { get; set; }
         public Function Function { get; set; }
+
+        public string MarshalVarPrefix { get; set; }
     }
 
     public abstract class MarshalPrinter : AstVisitor

src/Generator/Types/ITypePrinter.cs

@@ -47,6 +47,7 @@ namespace CppSharp.Types
 
         public TypePrinterContextKind Kind;
         public Declaration Declaration;
+        public Parameter Parameter;
         public Type Type;
     }
 

tests/Basic/Basic.Tests.cs

@@ -44,6 +44,16 @@ public class BasicTests
         Assert.That(hello.RetEnum(Enum.F), Is.EqualTo(-9));
     }
 
+    [Test]
+    public void TestPrimitiveOutParameters()
+    {
+        var hello = new Hello();
+
+        float f;
+        Assert.That(hello.TestPrimitiveOut(out f), Is.True);
+        Assert.That(f, Is.EqualTo(10.0f));
+    }
+
     [Test]
     public void TestNullRef()
     {

tests/Basic/Basic.cpp

@@ -95,6 +95,12 @@ Hello* Hello::RetNull()
     return 0;
 }
 
+bool Hello::TestPrimitiveOut(CS_OUT float* f)
+{
+    *f = 10;
+    return true;
+}
+
 int unsafeFunction(const Bar& ret, char* testForString, void (*foo)(int))
 {
     return ret.A;

tests/Basic/Basic.cs

@@ -15,6 +15,7 @@ namespace CppSharp.Tests
         {
             lib.SetClassAsValueType("Bar");
             lib.SetClassAsValueType("Bar2");
+            lib.SetMethodParameterUsage("Hello", "TestPrimitiveOut", 1, ParameterUsage.Out);
         }
 
         static class Program

tests/Basic/Basic.h

@@ -4,6 +4,8 @@
 #define DLL_API
 #endif
 
+#define CS_OUT
+
 class DLL_API Foo
 {
 public:
@@ -84,6 +86,9 @@ public:
 
     int RetEnum(Enum);
     Hello* RetNull();
+
+    bool TestPrimitiveOut(CS_OUT float* f);
+
 };
 
 class DLL_API AbstractFoo