Question

我尝试使用mysql-connector-c ++和G-WAN 4.3.14，这是我的原始源代码：

//#define USE_GWAN
#include<cstdio>
#include<iostream>
#include <cppconn/driver.h>
#include <cppconn/exception.h>
using namespace std;

#ifdef USE_GWAN
  #include "gwan.h"
  #pragma link mysqlcppconn
  #define print(x) xbuf_cat(get_reply(argv),x)
#else 
  #define print(x) printf(x)
#endif

int main(int argc,char** argv) {
  try {
    sql::Driver *driver = get_driver_instance();
    sql::Connection *con = driver->connect("tcp://127.0.0.1:3306", "secret", "secret");
    print("ok\n");
    delete con;
  } catch (sql::SQLException &e) {
    print("err\n");    
  }
  return 200;
}

当我尝试正常编译时，它工作正常：

g++ -lmysqlcppconn test.cpp

但是当我取消注释// #define USE_GWAN并在G-WAN上试用它时，它会显示：

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Warning: test.cpp
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/asd/gwan_linux64-bit/0.0.0.0_8088/#0.0.0.0/csp/test.cpp:
In function 'int main(int, char**)':
/csp/test.cpp:11:46: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
   #define print(x) xbuf_cat(get_reply(argv),x)
                                              ^
/csp/test.cpp:20:5: note: in expansion of macro 'print'
     print("ok\n");
     ^
/csp/test.cpp:11:46: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
   #define print(x) xbuf_cat(get_reply(argv),x)
                                              ^
/csp/test.cpp:23:5: note: in expansion of macro 'print'
     print("err\n");    
     ^

 8|#ifdef USE_GWAN
 9|  #include "gwan.h"
10|  #pragma link mysqlcppconn
11!  #define print(x) xbuf_cat(get_reply(argv),x)
12|#else 
13|  #define print(x) printf(x)
14|#endif
15|


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Linking test.cpp: undefined symbol: get_driver_instance
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/asd/gwan_linux64-bit/0.0.0.0_8088/#0.0.0.0/csp/test.cpp:
In function 'int main(int, char**)':
/csp/test.cpp:11:46: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
   #define print(x) xbuf_cat(get_reply(argv),x)
                                              ^
/csp/test.cpp:20:5: note: in expansion of macro 'print'
     print("ok\n");
     ^
/csp/test.cpp:11:46: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
   #define print(x) xbuf_cat(get_reply(argv),x)
                                              ^
/csp/test.cpp:23:5: note: in expansion of macro 'print'
     print("err\n");    
     ^

 8|#ifdef USE_GWAN
 9|  #include "gwan.h"
10|  #pragma link mysqlcppconn
11!  #define print(x) xbuf_cat(get_reply(argv),x)
12|#else 
13|  #define print(x) printf(x)
14|#endif
15|


To run G-WAN, you must fix the error(s) or remove this Servlet.

所有libs都已正确安装

/usr/lib/libmysqlclient.a
/usr/lib/libmysqlclient.so -> libmysqlclient.so.18*
/usr/lib/libmysqlclient.so.18 -> libmysqlclient.so.18.0.0*
/usr/lib/libmysqlclient.so.18.0.0*
/usr/lib/libmysqlclient_r.a -> libmysqlclient.a
/usr/lib/libmysqlclient_r.so -> libmysqlclient.so*
/usr/lib/libmysqlclient_r.so.18 -> libmysqlclient.so*
/usr/lib/libmysqlclient_r.so.18.0.0 -> libmysqlclient.so*
/usr/lib/libmysqlcppconn.so -> libmysqlcppconn.so.7*
/usr/lib/libmysqlcppconn.so.7 -> libmysqlcppconn.so.7.1.1.3*
/usr/lib/libmysqlcppconn.so.7.1.1.3*
/usr/lib/libmysqld.a
/usr/lib/libmysqld.so -> libmysqld.so.18*
/usr/lib/libmysqld.so.18*
/usr/lib/libmysqlservices.a

我应该添加什么来使用mysql-connector-c ++和G-WAN？

Answer 1

您没有编译或链接器错误，只是发出警告。

所以，你应该能够运行你的脚本了。

[UPDATE]

此外，在您的C ++脚本中， #pragma link 指令指定的库没有双引号。涉及编译指示指令的所有G-WAN示例都使用双引号 - 顺便说一下，C标准中的字符串是强制性的：

#pragma link "pqxx"
#pragma link "pq"

将MySQL与G-WAN结合使用

1 个答案: