将结构(或类)从C ++ dll传递到C#(Unity 3D) [英] Pass structure (or class) from C++ dll to C# (Unity 3D)

问题描述

我正在编写包装程序以从传感器获取一些数据.虽然我在传递int，float和它们的数组时没有问题，但是我很难掌握如何传递结构.

I am writing a wrapper to get some data from a sensor. While I have no problems with passing int, float and arrays of them, I have difficulties to grasp how to pass a structure.

代码摘要

C ++方面

结构如下:

struct HandInfo
{
    int id;
    float x, y, z;
};

在某个时候，一个静态的，全局可见的HandInfo leftHand填充了可通过以下包装函数检索的值:

At some point one static, globally visible HandInfo leftHand is filled with values which are retrievable through the following wrapper function:

extern EXPORT_API HandInfo MyWrapper_getLeftHand()
{
    return handtracker.getLeftHand();
}

其中 handtracker 只是包装类的一个实例.

where handtracker is just an instance of the wrapped class.

C#端

一旦声明了extern函数

Once declared the extern function

[DllImport("MyWrapper")]
private static extern HandInfo MyWrapper_getLeftHand();

在C#端，理想情况下，我将具有相同的结构类型

On the C# side, ideally, I would have the same struct type

public struct HandInfo
{
    public int id;
    public float x, y, z;
}

并分配一个变量

HandInfo hi = MyWrapper_getLeftHand(); // NAIVELY WRONG CODE

可以理解，这是行不通的.

which, understandably, doesn't work.

要实现这一目标的方式是什么?

What's the way to achieve this?

我将不胜感激. 谢谢大家的时间.

I'd appreciate any help. Thank you all for your time.

推荐答案

它应该可以正常工作(至少，在我拥有的一个小型C ++ + C#项目中，我能够使其与该struct一起工作)在x86和x64中)

It should work correctly (at least, here in a small C++ + C# project I have, I was able to make it work with that struct, both in x86 and x64)

[DllImport("MyWrapper.dll", CallingConvention = CallingConvention.Cdecl)]
private static extern HandInfo MyWrapper_getLeftHand();

唯一的事情是，必须声明CallingConvention = CallingConvention.Cdecl.

The only thing, you must declare the CallingConvention = CallingConvention.Cdecl.

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