在linux和windows用c++编写c接口的动态库

linux

动态的头文件api.h

#ifndef _API_H
#define _API_H

#ifdef DLL_IMPLEMENT
#define DLL_EXPORT extern "C"
#else
#define DLL_EXPORT
#endif

DLL_EXPORT int mysum(int a, int b);

#endif // _API_H

动态库的源文件api.cpp

#define DLL_IMPLEMENT

#include "api.h"
#include <iostream>

DLL_EXPORT int mysum(int a, int b)
{
    std::cout << "This (mysum) is a c++ function." << std::endl;
    return a + b;
}

调用动态库的测试代码main.c

#include <stdio.h>
#include "api.h"

int main()
{
    int sum = mysum(, );
    printf("The sum is %d\n", sum);
}

下面在命令行测试：

g++ -shared -fPIC -o libmyapi.so api.cpp    #生成动态库
gcc main.c -o a.out -L. -lmyapi    #链接动态库生成执行文件
ln -s /path/to/libmyapi.so /usr/lib/libmyapi.so    #在系统的动态库搜索路径建立软连接
ldconfig    #让系统重新搜索一遍动态库
./a.out    #执行，下面是输出
    This (mysum) is a c++ function.
    The sum is 11

windows

动态的头文件api.h

#ifndef _API_H
#define _API_H

#ifdef DLL_IMPLEMENT
#define DLL_EXPORT extern "C" __declspec(dllexport)
#else
#define DLL_EXPORT extern "C" __declspec(dllimport)
#endif

#define MYAPI __stdcall

DLL_EXPORT int MYAPI mysum(int a, int b);

#endif // _API_H

动态库的源文件api.cpp

#define DLL_IMPLEMENT

#include "api.h"
#include <iostream>int MYAPI mysum(int a, int b)
{
    std::cout << "This (mysum) is a c++ function." << std::endl;
    return a + b;
}

调用动态库的测试代码main.c

#include <stdio.h>
#include "api.h"
#pragma comment(lib, "./myapi.lib")

int main()
{
    int sum = mysum(, );
    printf("The sum is %d\n", sum);
}

windows在visual studio中测试即可

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