关于互操作性的几个问题 - 在C＃中使用的C ++导出函数 [英] Few questions on interopability - C++ exported functions to use in C#

问题描述

大家好，



我有一个用C ++编写的代码，我需要在C＃应用程序中使用。

下面是语法的我需要在C＃应用程序中使用的两种方法：

Hi All,

I have a code written in C++ which i need to consume in C# Application.
Below are the syntax's of the two methods which i need to use in my C# application:

long __declspec (dllimport) MyMethod1(const wchar_t* inputFileName, const wchar_t* outputFileName)

__declspec (dllimport) int __stdcall MyMethod2(void ** pMyVoidPtr, MY_CUSTOM_STRUCT* pMyCustomStruct);

我可以在我的C ++应用程序中使用它们，如下所示：

I could use them in my C++ Application as below:

MyMethod1(_T("C:\\InputFile.txt"), _T("C:\\OutputFile.txt"));

MY_CUSTOM_STRUCT myCustomStruct;

void* pVoidPtr = NULL;

MyMethod2(&pVoidPtr, &myCustomStruct);

在C ++应用程序中，我可以获得所需的结果。但是在C＃应用程序中，指针pVoidPtr总是返回NULL。



我尝试使用ref，输出IntPtr作为参数，但一切都失败了。



任何人都可以在C＃应用程序中为我提供相同的语法（对于这两种方法）？



谢谢和问候，
Kishor Reddy



我尝试过：

In C++ Application, i could get the desired results. But in C# Application, the Pointer pVoidPtr always returns NULL.

I have tried using ref, out IntPtr as parameters but everything failed.

Could anyone provide me the syntax for the same in C# Application (For both the methods)?

Thanks and Regards,
Kishor Reddy

What I have tried:

[DllImport("Exported Dll Path")]
long static extern MyMethod1(string strInputName, string strOutputName);

[DllImport("Exported Dll Path")]
int static extern MyMethod2(out IntPtr pVoidPtr, MY_CUSTOM_STRUCT myCustomStruct);

[DllImport("Exported Dll Path")]
int static extern MyMethod2(out IntPtr pVoidPtr, IntPtr myCustomStruct);

推荐答案

首先Garth是对的，你必须导出从外面访问它们的功能。



你不应该从一个运行时（C ++）导入内存或分配objext到另一个（C＃）。你不喜欢陷阱。从C＃中提供足够大的缓冲区，可能在询问C ++之后使用显式函数而不是分配并执行调用。



读取我的文章以一些简单的方式来处理这个问题。最后还是一个处理更复杂场景的链接。

At first Garth is right you must export the functions to access them from outside.

And you shouldnt import memory or allocated objext from one runtime (C++) into another (C#). You wont like the pitfalls. Provide a big enough buffer from C#, maybe after asking C++ with an explicit function and than allocate and execute the call.

Read my article for some simple way to deal that issue. At the end is also a link where a more complexer scenario is handled.

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