Question

I’m loading a libmysql.dll and want to connect to a db. When calling the mysql_real_connect i get a buffer overflow error. Why? Code:

#include <iostream>
#include <string.h>
#include <windows.h>
#include <cstdlib>
#include <stdio.h>
#include "mysql.h"

using namespace std;
// Definition des Types der DLL-Funktion, die verwendet werden soll
typedef int (*BinaryFunction_c) (int,string,string,string,string,int,int,int) ;
typedef int (*BinaryFunction_i) (int) ;

int main (void) 
{
    BinaryFunction_i    m_init  ;
    BinaryFunction_c    m_connect ;
    BOOL              fFreeResult ;
    int sqlinit;
    int connid;

    // DLL Datei laden
    HINSTANCE         hinstLib = LoadLibrary("./libmysql.dll");



    if (hinstLib != NULL)
    {
        // Die Einsprungadresse abfragen
        m_init = (BinaryFunction_i) GetProcAddress (hinstLib, "mysql_init") ;

        // Die Funktion aufrufen
        if ( m_init != NULL )
        {
            sqlinit = (*m_init) (NULL); 
            cout << dec << "m_init: " << m_init << endl;
        }
        else
        {
            cout << "fehler beim init" << endl;
        }

        //connect
        m_connect = (BinaryFunction_c) GetProcAddress (hinstLib, "mysql_real_connect");
        // Die Funktion aufrufen
        if ( m_connect != NULL )
        {
            connid= (*m_connect) (sqlinit, "192.168.1.2", "cashbot", "eck1234", "cashbot", 3306, NULL, 0);
            cout << "connid: " << connid << endl;
        }
        else
        {
            cout << "fehler beim connect" << endl;
        }

        // Die DLL-Datei wieder entladen
        fFreeResult = FreeLibrary (hinstLib) ;
    }

    return 0;
}

Answer 1

OK, the problem was that the 64 bit win7 searches for the 64-bit version of the libmysql.dll in the SysWOW64 folder and this dll does not work with a 32 programm!