2012-01-15 172 views
1

我有C++代码来连接并用mysql:CPP-mysql的未定义的引用“的功能”错误

#include <iostream> 
#include <mysql/mysql.h> 

using namespace std; 

MYSQL *connection, mysql; 
MYSQL_RES *result; 
MYSQL_ROW row; 
int query_state; 

int main() { 
mysql_init(&mysql); 

connection = mysql_real_connect(&mysql,"localhost","root","pass","cpp_data",0,0,0); 
if (connection == NULL) { 
cout << mysql_error(&mysql) << endl; 
return 1; 
} 
return 0; 
} 

当我编译,我得到test.cpp:(.text+0x11): undefined reference to 'mysql_init'mysql_real_connectmysql_error同样的错误。

我已经试过gcc -o test -L/usr/lib/mysql -lmysqlclient test.cpp,但这给我以下错误:

test.cpp:(.text+0x7a): undefined reference to `std::cout' 
test.cpp:(.text+0x7f): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)' 
test.cpp:(.text+0x87): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)' etc. 

我检查mysql.hmysql_real_connect的定义是:

MYSQL *  STDCALL mysql_real_connect(MYSQL *mysql, const char *host, 
         const char *user, 
         const char *passwd, 
         const char *db, 
         unsigned int port, 
         const char *unix_socket, 
         unsigned long clientflag); 

我没有问题,当我做不使用这些mysql函数。是否有另一个选择来解决这个问题?

回答

2

您需要编译并链接C++代码与g++而不是gcc。否则,C++标准库将无法正确链接。

+0

so g ++ -o test -L/usr/lib/mysql -lmysqlclient test.cpp实际上是解决这个问题的方法吗? – 2012-01-15 13:02:53

+0

对于未定义的符号,是的。 (尽管你应该在'test.cpp'后面加上'-lmysqlclient'作为该行的结尾。) – Mat 2012-01-15 13:03:45

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