C++连接Mysql数据库,mysql_real_connect总是报错:访问内存冲突

C++连接本地Mysql数据库,配置按照网上来的:
c/c++使用VS2013连接mysql数据库
访问数据库的代码也是按照网上来的:

 #include <winsock.h>
#include <iostream>
#include <string>
#include <mysql.h>
using namespace std;
#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib, "libmysql.lib")

//单步执行,不想单步执行就注释掉
#define STEPBYSTEP

int main() {
    cout << "****************************************" << endl;

#ifdef STEPBYSTEP
    system("pause");
#endif

    //必备的一个数据结构
    MYSQL mydata;

    //初始化数据库
    if (0 == mysql_library_init(0, NULL, NULL)) {
        cout << "mysql_library_init() succeed" << endl;
    } else {
        cout << "mysql_library_init() failed" << endl;
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //初始化数据结构
    if (NULL != mysql_init(&mydata)) {
        cout << "mysql_init() succeed" << endl;
    } else {
        cout << "mysql_init() failed" << endl;
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //在连接数据库之前,设置额外的连接选项
    //可以设置的选项很多,这里设置字符集,否则无法处理中文
    if (0 == mysql_options(&mydata, MYSQL_SET_CHARSET_NAME, "gbk")) {
        cout << "mysql_options() succeed" << endl;
    } else {
        cout << "mysql_options() failed" << endl;
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //连接数据库
    if (NULL
            != mysql_real_connect(&mydata, "localhost", "root", "test", "test",
                    3306, NULL, 0))
            //这里的地址,用户名,密码,端口可以根据自己本地的情况更改
            {
        cout << "mysql_real_connect() succeed" << endl;
    } else {
        cout << "mysql_real_connect() failed" << endl;
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //sql字符串
    string sqlstr;

    //创建一个表
    sqlstr = "CREATE TABLE IF NOT EXISTS user_info";
    sqlstr += "(";
    sqlstr +=
            "user_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'Unique User ID',";
    sqlstr +=
            "user_name VARCHAR(100) CHARACTER SET gb2312 COLLATE gb2312_chinese_ci NULL COMMENT 'Name Of User',";
    sqlstr +=
            "user_second_sum INT UNSIGNED NOT NULL DEFAULT 0 COMMENT 'The Summation Of Using Time'";
    sqlstr += ");";
    if (0 == mysql_query(&mydata, sqlstr.c_str())) {
        cout << "mysql_query() create table succeed" << endl;
    } else {
        cout << "mysql_query() create table failed" << endl;
        mysql_close(&mydata);
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //向表中插入数据
    sqlstr =
            "INSERT INTO user_info(user_name) VALUES('公司名称'),('一级部门'),('二级部门'),('开发小组'),('姓名');";
    if (0 == mysql_query(&mydata, sqlstr.c_str())) {
        cout << "mysql_query() insert data succeed" << endl;
    } else {
        cout << "mysql_query() insert data failed" << endl;
        mysql_close(&mydata);
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //显示刚才插入的数据
    sqlstr = "SELECT user_id,user_name,user_second_sum FROM user_info";
    MYSQL_RES *result = NULL;
    if (0 == mysql_query(&mydata, sqlstr.c_str())) {
        cout << "mysql_query() select data succeed" << endl;

        //一次性取得数据集
        result = mysql_store_result(&mydata);
        //取得并打印行数
        int rowcount = mysql_num_rows(result);
        cout << "row count: " << rowcount << endl;

        //取得并打印各字段的名称
        unsigned int fieldcount = mysql_num_fields(result);
        MYSQL_FIELD *field = NULL;
        for (unsigned int i = 0; i < fieldcount; i++) {
            field = mysql_fetch_field_direct(result, i);
            cout << field->name << "\t\t";
        }
        cout << endl;

        //打印各行
        MYSQL_ROW row = NULL;
        row = mysql_fetch_row(result);
        while (NULL != row) {
            for (int i = 0; i < fieldcount; i++) {
                cout << row[i] << "\t\t";
            }
            cout << endl;
            row = mysql_fetch_row(result);
        }

    } else {
        cout << "mysql_query() select data failed" << endl;
        mysql_close(&mydata);
        return -1;
    }

#ifdef STEPBYSTEP
    system("pause");
#endif

    //删除刚才建的表
    sqlstr = "DROP TABLE user_info";
    if (0 == mysql_query(&mydata, sqlstr.c_str())) {
        cout << "mysql_query() drop table succeed" << endl;
    } else {
        cout << "mysql_query() drop table failed" << endl;
        mysql_close(&mydata);
        return -1;
    }
    mysql_free_result(result);
    mysql_close(&mydata);
    mysql_server_end();

    system("pause");
    return 0;
}

但是mysql_options总是报错:堆坏损
mysql_real_connect 总是报错:访问内存冲突
肿么破?

2个回答

lan_mmm
hoestelan 啊, 你一说指针,我忽然就懂了,感觉源代码里面一开始用的就不是指针= =
接近 5 年之前 回复

//连接数据库
if (NULL
!= mysql_real_connect(&mydata, "localhost", "root", "test", "test",
3306, NULL, 0))
//这里的地址,用户名,密码,端口可以根据自己本地的情况更改
{
cout << "mysql_real_connect() succeed" << endl;
} else {
cout << "mysql_real_connect() failed" << endl;
*************
mysql_close(&mydata);
mysql_library_end();
*************
return -1;
}

    看看是不是这个问题, 没有及时释放乐内存
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