c# - 数组大小超出寻址限制(C# 与 C++)

Question

我有一个 C# 程序来管理复杂的巨大数组(大于 2GB)。该程序在 x64 中编译，在 App.config 中使用 gcAllowVeryLargeObjects=true 子句:

<configuration>
  <runtime>
    <gcAllowVeryLargeObjects enabled="true" />
  </runtime>
</configuration>

它需要使用第三方 dll，但是当将这些巨大的数组传递给这个外部函数时，编码似乎失败了。

这是异常“Array size exceeds addressing limitation”

这似乎是一个 VS CLR 问题，因为我做了这个例子来演示它。

class Program
{
    static void Main(string[] args)
    {
        MyWrapper.MyTest();
    }
}

[SuppressUnmanagedCodeSecurity]
public class MyWrapper    
{


    private MyWrapper()
    {
    }

    internal static int CS_foo(
    [In] Complex[,] A // text to prepend to converted integer
     )
    {
         Complex B_complex= new Complex(0, 0);
        for (int i = 0; i< 10; i++)
        {

            B_complex = A[0, i];
            Console.WriteLine(string.Format(" from C# A({0})\t{1}\ti{2}", i, B_complex.Real, B_complex.Imaginary));
        }
        return 0;
    }

    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
    [DllImport("DLL1.dll", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true, SetLastError = false)]
    internal static extern int C_foo(     
      [In] Complex[,] A// text to prepend to converted integer

     );


    public static void MyTest()
    {
        Complex[,]A = new Complex[12000, 12000];

        A[0, 0] = new Complex(0.1, -0.1);
        A[0, 1] = new Complex(11.0, 0.1);
        A[0, 5] = new Complex (55, -0.5);
        A[0, 9] = new Complex (99.0, 0.9);

        MyWrapper.CS_foo(A);
        MyWrapper.C_foo(A); //Here Fails!!            
    }
}

C++ DLL 代码:

#include "stdafx.h"
#include "stdio.h"


#ifndef Complex16
typedef
struct Complex16 {
    double real;
    double imag;
} Complex16;
#endif

extern "C" int __declspec(dllexport)  C_foo(
    Complex16* A 
    )

{
    Complex16  B;
    for (int i = 0; i < 10; i++)
    {       
    B.real = A[i].real;
    B.imag = A[i].imag;
    printf("   hello from C A(%d)=( %f %f ) \n ", i, B.real, B.imag);
    }
    return 0;
}

如果您更改数组大小(例如 1200x1200)，则该示例有效!知道如何解决这个问题吗？

他京

Answer 1

可以在这里找到解决方案:https://social.msdn.microsoft.com/Forums/vstudio/en-US/b02c61ab-8be1-4ed1-9752-9fa24211d78a/c-vs-c-array-size-exceeds-adressing-limitation?forum=csharpgeneral

简而言之:

默认编码不喜欢这么大的数组。固定数组并将指向其第一个元素的指针传递给 native 函数:

using System.Numerics;
using System.Runtime.InteropServices;

public unsafe class MyWrapper
{
    static void Main(string[] args)
    {
        Complex[,] A = new Complex[12000, 12000];

        A[0, 0] = new Complex(0.1, -0.1);
        A[0, 1] = new Complex(11.0, 0.1);
        A[0, 5] = new Complex(55, -0.5);
        A[0, 9] = new Complex(99.0, 0.9);

        fixed (Complex* p = &A[0, 0])
            C_foo(p);
    }

    [DllImport("DLL1.dll", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true, SetLastError = false)]
    internal static extern int C_foo(Complex* A);