GCHandle.FromIntPointer不能按预期工作

问题描述

这是一个非常简单(完整)的程序，用于练习使用GCHandle.FromIntPointer:

Here's a very simple (complete) program for exercising the use of GCHandle.FromIntPointer:

using System;
using System.Runtime.InteropServices;

namespace GCHandleBugTest
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = new int[10];

            GCHandle handle = GCHandle.Alloc(arr, GCHandleType.Pinned);
            IntPtr pointer = handle.AddrOfPinnedObject();
            GCHandle handle2 = GCHandle.FromIntPtr(pointer);
        }
    }
}

请注意，该程序本质上是对英语中在 CLR通过C#(4e )(第547页).但是，运行它会导致不受管理的异常，例如:

Note that this program is essentially a transliteration of the procedure described in English on CLR via C# (4e) on page 547. Running it, however, results in an unmanaged exception like:

Additional Information: The runtime has encountered a fatal error. The address of the error was at 0x210bc39b, on thread 0x21bc. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack.

认为这可能是.NET 4.5中的错误，并且由于我没有发现明显的错误，因此我在Linux(v2.10.8.1)上的Mono中尝试了完全相同的程序.我得到了更多一些信息，但仍然令人困惑的异常GCHandle value belongs to a different domain.

Thinking that this might be a bug in .NET 4.5, and since I don't see anything obviously wrong, I tried exactly the same program in Mono on Linux (v2.10.8.1). I got the slightly more informative but still puzzling exception GCHandle value belongs to a different domain.

据我所知，handle确实与我调用GCHandle.FromIntPtr的代码属于同一个AppDomain.但是，我在两个实现中都看到一个例外，这一事实使我怀疑我缺少一些重要的细节.这是怎么回事?

As far as I am aware, the handle really does belong to the same AppDomain as the code where I call GCHandle.FromIntPtr. But the fact that I see an exception in both implementations makes me suspect that I am missing some important detail. What's going on here?

推荐答案

AddrOfPinnedObject与FromIntPtr相反.您需要ToIntPtr代替:

AddrOfPinnedObject is not the opposite of FromIntPtr. You want ToIntPtr instead:

IntPtr pointer = handle.ToIntPtr ();
GCHandle handle2 = GCHandle.FromIntPtr (pointer);

FromIntPtr不使用对象的地址，而是使用一个不透明的值(恰好定义为IntPtr)，该值用于使用ToIntPtr检索对象.

FromIntPtr does not take the address of the object, it takes an opaque value (which happens to be defined as IntPtr), which is used to retrieve the object with ToIntPtr.

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