用g++编译动态链接库

　　写了一个最简单的动态链接库程序，使用g++命令行编译。怕以后忘记，就把它记到blog中。

动态库导出头文件:

/**
  * file: dll.h
  * Powered by JGood 2009-09-22
  */

#ifndef __dll_h__
#define __dll_h__

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

DLL_EXPORT int jmax(int x, int y);

#endif

 

动态库实现：

编译成obj文件：g++ -c -o dll.obj dll.cpp

链接obj，生成dll: g++ -shared -o dll.so dll.obj

/**
  * file: dll.cpp
  * Powered by JGood 2009-09-22
  */

#define __MY_DLL_LIB__
#include "dll.h"

int jmax(int x, int y)
{
    return x > y ? x : y;
}

 

调用动态库：

直接编译成exe: g++ main.cpp dll.so -o main.exe

/**
  * file: main.cpp
  * Powered by JGood 2009-09-22
  */

#include "dll.h"
#include 

using namespace std;

int main()
{
    int a = 20;
    int b = 40;
    
    cout << jmax(a, b) << endl;

    return 0;
}