C#调用C++接口

作者：追风剑情发布于：2020-6-28 18:01 分类：C#

一、VS新建C++空项目

CTestDll.h

#ifndef __CTEST_DLL_H
#define __CTEST_DLL_H
// 声明为C编译、链接方式为外部函数
extern "C" _declspec(dllexport) int _cdecl add(int* x, int* y);
extern "C" _declspec(dllexport) int _cdecl sub(int x, int y);
#endif

CTestDll.cpp

#include "CTestDll.h"
 
#ifdef __cplusplus //如果是cpp文件
extern "C" //这部分代码按C编译
{
	int add(int* x, int* y)
	{
		return *x + *y;
	}
 
	int sub(int x, int y)
	{
		return x - y;
	}
}
#endif

可能会出现的报错

重定义解决方法 (调用约定要与代码中写的一致)

不兼容解决方法

二、VS新建C#控制台项目

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;
 
namespace ConsoleApp6
{
    class Program
    {
        [DllImport(@"Dll4.dll", EntryPoint = "add", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Cdecl)]
        public static extern int add(ref int x, ref int y);
        [DllImport(@"Dll4.dll", EntryPoint = "sub", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Cdecl)]
        public static extern int sub(int x, int y);
 
        static void Main(string[] args)
        {
            int x = 6, y = 5;
            int a = add(ref x, ref y);
            int b = sub(x, y);
            Console.WriteLine("a={0}, b={1}", a, b);
            Console.Read();
        }
    }
}