时间戳

首页 > 解决方案 > 链接时未定义对“check(std::string const&)”的引用

c++ - 链接时未定义对“check(std::string const&)”的引用

问题描述

我在 C++ 中有一些“简单”代码来连接到 MySQL 数据库（这是 localhost，顺便说一句）。

#include <stdlib.h>
#include <iostream>
#include "mysql/include/mysql/jdbc.h"


using namespace sql;


int main() {

  std::cout << "Test"<< std::endl;

  try {
   sql::Driver *myDriver;
   sql::Connection *myConn;
   sql::Statement *myStmt;
   sql::ResultSet *myRes;

   myDriver = sql::mysql::get_mysql_driver_instance();
   myConn = myDriver ->connect("tcp://127.0.0.1", "root", "");
   myConn->setSchema("root");

   myStmt = myConn->createStatement();
   myRes = myStmt->executeQuery("SELECT 'Hello World' AS _message");

   while (myRes->next()) {
     std::cout << myRes->getString("_message") << std::endl;
   }
   delete myRes;
   delete myStmt;
   delete myConn;

 } catch (sql::SQLException &e) {
   std::cout << "Filed connect to Database" << std::endl;
   std::cout << "Error: " << e.what() << std::endl;
   std::cout << "Error code: " << e.getErrorCode() << std::endl;
 }
}

该文件与头文件jdbc.h有很多不同#include。

我使用 2 个命令来编译： g++ -c -Wall -I/usr/include/cppconn connect.cpp -o connect.o和 g++ -lm -L/usr/lib/x86_64-linux-gnu -lmysqlcppconn connect.o -o connect

这产生了这个链接错误：

/usr/bin/ld: connect.o: in function "check_lib()':
connect.cpp:(.text+0x2c): undefined reference to `check(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
/usr/bin/ld: connect.cpp:(.text+0x77): undefined reference to "check(std::map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > const&)"
/usr/bin/ld: connect.o: in function `sql::mysql::get_driver_instance_by_name(char const*)':
connect.cpp:(.text+0xfa): undefined reference to   "sql::mysql::_get_driver_instance_by_name(char const*)"
collect2: error: ld returned 1 exit status

我用这个答案解决了这个问题：https ://stackoverflow.com/a/33395489/14814564 ，基本上是放在#define _GLIBCXX_USE_CXX11_ABI 0 文件的顶部，编译后会产生这个链接错误：

/usr/bin/ld: connect.o: in function "check_lib()':
connect.cpp:(.text+0x2c): undefined reference to "check(std::string const&)'
/usr/bin/ld: connect.cpp:(.text+0x77): undefined reference to "check(std::map<std::string, std::string, std::less<std::string>, std::allocator<std::pair<std::string const, std::string> > > const&)'
/usr/bin/ld: connect.o: in function `sql::mysql::get_driver_instance_by_name(char const*)':
connect.cpp:(.text+0xfa): undefined reference to "sql::mysql::_get_driver_instance_by_name(char const*)'
collect2: error: ld returned 1 exit status

为什么此链接错误不断弹出，我该如何解决？

标签： c++linker-errorsmysql-connector

解决方案

推荐阅读