在C＃中导入C DLL，如何将短**型 [英] Import C dll in C# , how to convert short** type

问题描述

我要导入C＃一个DLL这是在C语言编码。以下是我要调用的函数的甲

I want to import a dll in C# which is coded in C language. The following is the formate of the function I want to call.

/*
*ReadAnswer
*@param objectID         The answer object ID
*@param answerBuf        The answer buffer.This buffer is automatically allocated by 
                         the function. 
                         It is automatically recycled with each call. A call to this 
                         function with an empty answer or a new request will 
                         automatically free the allocated buffer.
*@param answerBufferSize The answer buffer size.This function return the size of the 
                         allocated buffer in this parameter.

*@return 0 if error occurs
        1 if success
*/

int ReadAnswer(unsigned short *objectID, 
               unsigned short **answerBuf, unsighed short *answerBufferSize )

请帮我一下吧。我被这个功能被卡住。谢谢你在前进

Please help me with it. I'm stucked by this function. Thank you in advance.

推荐答案

函数应声明如下：

[DllImport(dllname)]
private extern static int ReadAnswer(
    out ushort objectID,
    out IntPtr answerBuf,  
    out ushort answerBufferSize
);

这样称呼它：

Call it like this:

ushort objectID, answerBufSize;
IntPtr answerBufPtr;
int retval = ReadAnswer(out objectID, out answerBufPtr,
    out answerBufSize);
if (retval == 0)
    // handle error
ushort[] answerBuf = new ushort[answerBufSize/2];
Marshal.Copy(answerBufPtr, (Int16[])answerBuf, 0, answerBuf.Length);

我的假设是， answerBufSize 的大小在字节。

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