C/C++ 连接 MySQL (GCC 版)

1、从 mysql-noinstall-5.1.30-win32.zip 包中解压 include, lib 两个目录到
使用C:\vcprojects\mysql-5.1.30 中

2、参考本博客《Windows XP下MinGW的安装与配置 》建好 Windows 下 GCC 的开发环境。

3、进入目录C:\vcprojects\mysql-5.1.30\lib\opt执行命令：
reimp -d libmysql.lib
dlltool -k -d libmysql.def -l libmysql.a

生成gcc所需链接的mysql库 libmysql

4、在C:\vcprojects\learn目录下创建文件 visitsql.c (网友代码修改版)

#include <windows.h>
#include <iostream>
#include <mysql.h>
#include <stdio.h>

using namespace std;

int main()
{
    //connection params
    //FILE *file;
    char *host = "localhost";
    char *user = "root";
    char *pass = "12345";
    char *db = "mysql";
    
    //sock
    MYSQL *sock;
    MYSQL_RES *results;
    MYSQL_ROW record;
    sock = mysql_init(0);
    if (sock) 
        cout << "sock handle ok!" << endl;
    else 
    {
        cout << "sock handle failed!" << mysql_error(sock) << endl;
    }

    //connection
    if (mysql_real_connect(sock, host, user, pass, db, 0, NULL, 0))
        cout << "connection ok!" << endl;
    else 
    {
        cout << "connection fail: " << mysql_error(sock) << endl;
    }
    mysql_set_character_set(sock,"gb2312");
    
    //connection character set
    cout << "connection character set: " << mysql_character_set_name(sock) << endl;

    //wait for posibility to check system/mysql sockets
    if(mysql_query(sock,"select * from user"))
    {
        cout<<"very good!"<<endl;                            
    }
    results=mysql_store_result(sock);
    printf("主机\t用户名\n");
    while(record = mysql_fetch_row(results))
    {
        printf("%s\t%s \n",record[0],record[1]);
    }
    mysql_free_result(results);
    //system("PAUSE");
    
    //closing connection
    mysql_close(sock);

    return EXIT_SUCCESS;
}

5、创建一个批处理文件 build.bat：
set MYSQL_CLIB=C:\vcprojects\mysql-5.1.30

set C_INCLUDE_PATH=%C_INCLUDE_PATH%;%MYSQL_CLIB%\include
set CPLUS_INCLUDE_PATH=%CPLUS_INCLUDE_PATH%;%MYSQL_CLIB%\include
set LIBRARY_PATH=%LIBRARY_PATH%;%MYSQL_CLIB%\lib\opt

g++ -o visitsql visitsql.c -llibmysql

执行该批处理，生成 visitsql.exe 执行该程序结果：
sock handle ok!
connection ok!
connection character set: gb2312
主机    用户名
localhost       root

6、比较visitsql 大小：
gcc 版          488KB
vc++ debug 版   40KB
vc++ release 版 10KB

7、另从网上摘抄
如果你的dlltool产生的libmysql.a是空文件的话，如下操作：
cd {mysql}/lib/opt
reimp libmysql.lib
dlltool.exe -d {mysql++}/libmysqlclient.def -e mysqlclient.exp -l mysqlclient.a -S as

备注：
mingw-utils-0.3.tar.gz
binutils-2.17.50-20060824-1.tar.gz

//reimp mysqlclient.lib
//ar rcs libmysqlclient.a *.obj
//rm *.obj

我对 gcc 了解不多，这段不知道何意，先记下来。