[IronPython] DynamicMethod question

[Haibo Luo]

I believe the main issue your code has is the parameter type: it should be typeof(int).MakeByRefType().

The following code print 20, 10 successfully.

---------------------------

public delegate int ByRefDelegate(out int a);

class Repro {
    static void Main(string[] args) {
        DynamicMethod m1 = new DynamicMethod("test", typeof(int), new Type[] { typeof(int).MakeByRefType() }, typeof(Repro).Module);
        m1.DefineParameter(1, ParameterAttributes.Out, "test");

        ILGenerator g = m1.GetILGenerator();
        g.Emit(OpCodes.Ldarg_0);
        g.Emit(OpCodes.Ldc_I4_S, 10);
        g.Emit(OpCodes.Stind_I4);
        g.Emit(OpCodes.Ldc_I4_S, 20);
        g.Emit(OpCodes.Ret);

        ByRefDelegate del = (ByRefDelegate)m1.CreateDelegate(typeof(ByRefDelegate));
        int b;
        Console.WriteLine(del(out b));
        Console.WriteLine(b);
    }

    static int Method(out int a) {
        a = 10;
        return 20;
    }
}

-----Original Message-----
From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Andrew Deren
Sent: Monday, May 29, 2006 11:04 PM
To: 'Discussion of IronPython'
Subject: [IronPython] DynamicMethod question

I know the question is not directly related to IP, but I know IP uses
dynamic methods and some people know quite a bit about them.

I need to create dynamic method that takes params by ref or out. Dynamic
method has DefineParameter method that I can use to define
ParameterAttributes.Out, but no ref.
But even if I use Out, I get exception when creating delegate:
Error binding to target method.

A sample code I tried:
public delegate int ByRefDelegate(out int a);

                        Module module = typeof(Test1).Module;
                        DynamicMethod m1 = new DynamicMethod("test",
typeof(int), new Type[] { typeof(int) }, module);
                        m1.DefineParameter(1, ParameterAttributes.Out,
"test");

                        ILGenerator g = m1.GetILGenerator();
                        g.Emit(OpCodes.Ldarg_0);
                        g.Emit(OpCodes.Neg);
                        g.Emit(OpCodes.Starg, 0);
                        g.Emit(OpCodes.Ret);

                        ByRefDelegate del =
(ByRefDelegate)m1.CreateDelegate(typeof(ByRefDelegate));

So I was just wondering if it's possible to have out or ref DynamicMethod?

Thanks.


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