Question

我试图用C＃调用用C编写的外部DLL函数，这是来自C的DLLEXPORT代码：

DLLEXPORT int DLLCALL Compress(int compressLevel, const unsigned char *srcBuf, unsigned char **outBuf, unsigned long *Size);

这是我从C＃调用该函数的代码：

[DllImport("test.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int Compress(int compressLevel, ref byte[] srcBuf, ref byte[] outBuf, Uint64 size);

...
byte[] buffer = new byte[1000];
byte[] _compressedByteArray = null;
Uint64 OutSize = 0;
Compress(10, buffer , compressedByteArray, OutSize);

然而，我的调用代码出错：＆＃34;尝试读取或写入受保护的内存。这通常表明其他内存已损坏。＆＃34;

我的声明是否有任何错误？任何纠正这个问题的想法都会非常感激。

Answer 1

尝试以下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace ConsoleApplication49
{
    class Program
    {
        [DllImport("XXXXX.dll", CallingConvention = CallingConvention.Cdecl)]
        public static extern int Compress(int compressLevel, IntPtr srcBuf, IntPtr outBuf, IntPtr size);   

        static void Main(string[] args)
        {
            int compressLevel = 0;
            string input = "The quick brown fox jumped over the lazy dog";
            IntPtr srcBuf = Marshal.StringToBSTR(input);
            IntPtr outBuf = IntPtr.Zero;
            IntPtr size = Marshal.AllocHGlobal(sizeof(long));
            int results =  Compress(compressLevel, srcBuf, outBuf, size);

            string output = Marshal.PtrToStringAnsi(outBuf);
            long longSize = Marshal.ReadInt64(size);
        }
    }
}

C unsigned char **和unsigned long * to C＃

1 个答案: