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Link error when using polymorphism [message #15669]

Sat, 03 May 2008 20:14

lucpolak
Messages: 18
Registered: April 2008
Location: France

Promising Member

Hi all,
i'm Lucas and i'm new in using TheIDE. I have a problem.

I have an abstract class named DBConnector and a derived class MySqlConnector.
When compiling, all is ok but i always have the link error :

vtable for VirtualSofts::SQL::DBConnector(referenced from d:\ultimate++\out\easybat\mingw.debug_full.gui.main.noblitz\ erpsystem.o:290; .text$_ZN12VirtualSofts3SQL11DBConnectorC2Ev; Vir
tualSofts::SQL::DBConnector::DBConnector(void); VirtualSofts::SQL::DBConnector::DBConnector())

I've tried to declare a constructor for DBConnector but the problem persists.

Here the code of DBConnector :

namespace VirtualSofts
{
	namespace SQL
	{
		class DBConnector
		{
		protected:
			bool			m_Connected;
			String			m_errorState;

		public:
			virtual ~DBConnector()
			{
				Disconnect();
			}
			//------------------------------------------
			// Acc�s � la base
			//------------------------------------------
			virtual bool Connect(String db);
			virtual bool Disconnect();

			//------------------------------------------
			// Accesseurs
			//------------------------------------------
			inline bool IsConnected() const { return m_Connected; }

			//------------------------------------------
			// Ex�cution de requ�tes
			//------------------------------------------
			virtual int SQLExecDML(const String &request);
			virtual cResultSet SQLExecQuery(const String &request);

			//------------------------------------------
			// Gestion des Erreurs
			//------------------------------------------
			String GetLastError() const {return m_errorState;}

		};
	}
}

and here the code of MySQLConnector :

namespace VirtualSofts
{
	namespace SQL
	{
		class MySQLConnector: public DBConnector
		{
                    //...

		public:
			//------------------------------------------
			// Acc�s � la base
			//------------------------------------------
			virtual bool Connect(String db);
			virtual bool Disconnect();

			//------------------------------------------
			// Ex�cution de requ�tes
			//------------------------------------------
			virtual int SQLExecDML(const String &request);
			virtual cResultSet SQLExecQuery(const String &request);

		};
	}
}

The problem appears when i instantiate the object by this way :
DBConnector *dbcnx = new MySQLConnector();

The code is ok ?
If i not use the virtual functions, all is ok...

Thanks for help ^^,

Lucas

[Updated on: Thu, 23 December 2010 14:48]

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