C# 调用 c++ dll

首先 c++ 库 dll 要定义

代码中定义 CPP_EXPORTS

#ifdef LASERSDK_EXPORTS
#define CPP_EXPORTS __declspec(dllexport)
#else
#define CPP_EXPORTS __declspec(dllimport)
#endif
编译器定义

LASERSDK_EXPORTS

普通函数

c++

extern "C" CPP_EXPORTS int __stdcall Add(int n1, int n2);

int __stdcall Add(int n1, int n2)
{
return n1 + n2;
}
c#

[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int Add(int n1, int n2);

// 使用
int res = Add(1, 1);

结构体

c++

struct Vector4
{
float A, B, C;
const char* D = nullptr;
};

extern "C" CPP_EXPORTS Vector4 __stdcall Add2(int n1, int n2);
extern "C" __declspec(dllexport) void __stdcall Add5(Vector4 vec);

// 结构体指针
// c++ 开启的内存，c++ 回收 Add7_Clear
extern "C" __declspec(dllexport) Vector4* __stdcall Add7();
extern "C" __declspec(dllexport) void __stdcall Add7_Clear(Vector4* vc);

// cpp
Vector4 __stdcall Add2(int n1, int n2)
{
Vector4 sd;
sd.A = 12;
sd.B = 13;
sd.D = "asdfssssws";
return sd;
}

void __stdcall Add5(Vector4 vec)
{
printf("\n Add5:: \n");
```
  printf("%f ,", vec.A);
  printf("%s ,", vec.D);

  printf("\n");
```
}

Vector4* __stdcall Add7()
{
Vector4* vec = new Vector4();
vec->A = 1212;
vec->D = new char[10000];
return vec;
}

void __stdcall Add7_Clear(Vector4* vc)
{
if (vc)
{
if (vc->D)
{
delete vc->D;
}
delete vc;
}
}
c#

[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern Vector4 Add2(int n1, int n2);

[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern void Add5(Vector4 vec);

[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern IntPtr Add7();
[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern void Add7_Clear(IntPtr vc);

// 使用
Vector4 sd = Add2(1, 1);
string s = Marshal.PtrToStringAnsi(sd.D);
Console.WriteLine("asdfasdfasdf : " + s);

Vector4 _vec = new Vector4();
_vec.A = 123;
_vec.D = Marshal.StringToHGlobalAnsi("dddddddddsdsdsdsdsbsbsbsbsbsbsb");

Add5(_vec);
Marshal.FreeHGlobal(_vec.D);

IntPtr add7 = Add7();

Vector4 _vec7 = (Vector4)Marshal.PtrToStructure(add7, typeof(Vector4));
Console.WriteLine(_vec7.A);

Add7_Clear(add7);

数组

c++

extern "C" CPP_EXPORTS int __stdcall arraytest(float* vals, int len);

int __stdcall arraytest(float* vals, int len)
{
```
  for (int i = 0; i < len; i++)
  {
      vals[i] = i;
  }
  return 0;
```
}
c#

[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int arraytest( float[] datas,int len);

// use

float[] one_outlines = new float[1024];
int res = arraytest(one_outlines, 1024);

回调函数

c++

typedef void (callback_outline)(int, float, int);
extern "C" CPP_EXPORTS void __stdcall laser_set_callback_outline_handle(callback_outline cb);

callback_outline _callback_outline;
float vals[1024];

void __stdcall laser_set_callback_outline_handle(callback_outline cb)
{
_callback_outline = cb;
```
  printf("laser_set_callback_outline_handle suc \n");

  if (_callback_outline)
  {
  	_callback_outline(1, vals, 1024);
  }
```
}
c#

// 映射c++函数
[DllImport("SampleCppWrapper.dll", CallingConvention = CallingConvention.StdCall)]
public static extern void laser_set_callback_outline_handle(CallbackOutlineDelegate call);

// 创建委托
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate void CallbackOutlineDelegate(int handle, [MarshalAs(UnmanagedType.LPArray, SizeConst = 1024)] float[] ydata, int len);

// use

// 回调函数
public static void CallbackOutlineFunc(int handle, [MarshalAs(UnmanagedType.LPArray, SizeConst = 1024)] float[] ydata, int len)
{

}

static LaserSdk.CallbackOutlineDelegate outlineDelegate;
static void Main1(string[] args)
{
outlineDelegate = new LaserSdk.CallbackOutlineDelegate(CallbackOutlineFunc);
laser_set_callback_outline_handle(outlineDelegate);

}