error 126 - The specified module could not be found.

[julof26]

Hi everyone,
Ive been just learning how to make/use dll files and Ive come up with thiss error (through getLastError() func). The code which creates the dll is almost the same as the IDE generated, I just changed the function name and what the function does, this is the code:
header file

#ifndef __MAIN_H__
#define __MAIN_H__

#include <windows.h>

/*  To use this exported function of dll, include this header
 *  in your project.
 */

#define DLL_EXPORT __declspec(dllexport)

#ifdef __cplusplus
extern "C"
{
#endif

int DLL_EXPORT getDungeonsNumber();

#ifdef __cplusplus
}
#endif

#endif // __MAIN_H__ 

cpp file

#include "main.h"

// a sample exported function
int DLL_EXPORT getDungeonsNumber()
{
    return 5;
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    switch (fdwReason)
    {
        case DLL_PROCESS_ATTACH:
            // attach to process
            // return FALSE to fail DLL load
            break;

        case DLL_PROCESS_DETACH:
            // detach from process
            break;

        case DLL_THREAD_ATTACH:
            // attach to thread
            break;

        case DLL_THREAD_DETACH:
            // detach from thread
            break;
    }
    return TRUE; // succesful
}

this makes the MW.dll file (CodeBlocks IDE used here).
Then the main program code is made in Qt IDE:

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;            //creates the main window of the app
    w.show();
    
    return a.exec();
}

//heres the c´tor of the main window where Im trying to load the dll and there comes the error

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow),
    DungeonsNumber(0),
    getDungeonsNumber(NULL)   
/*getDungeonsNumber is pointer to func of type FUNCPTgetDungeonsNumber which I have defined in another header included in the mainwindow.h 
its defined like this typedef int (*FUNCPTgetDungeonsNumber)(); */
{
    ui->setupUi(this);

    SetDllDirectory(NULL);
    hinstDLL = LoadLibrary((LPCWSTR)"MW.dll");
    if(hinstDLL!=0)
        getDungeonsNumber = (FUNCPTgetDungeonsNumber)GetProcAddress(hinstDLL, "getDungeonsNumber");
    else{
        Error::cannotLoadDLL();   //just my function to handle the error
    }
    if(getDungeonsNumber==NULL)
        Error::nullFunction();  //just another my function to handle the error

    DungeonsNumber = getDungeonsNumber();
    QMessageBox::information(this, "a", QString::number(DungeonsNumber));

    FreeLibrary(hinstDLL);
}
.
.
.

static void Error::cannotLoadDLL(){
        int e = GetLastError();
        QString str = "Your DLLs seems to be broken... ";
        str += "getLastError() returned value: ";
        str += QString::number(e);
        QMessageBox::critical(NULL, "Error", str);
    }

the function Error::cannotLoadDLL() is called and the messagebox sais the getLastError returned value 126.

I have the dll file in the axact place as the executable. Also i have tried to load some profi made dlls like msvcr100d.dll and get the same error. This is very frustating, hope someone can help :D

[modoran]

What is this ?

hinstDLL = LoadLibrary((LPCWSTR)"MW.dll");

The cast here is absolutely wrong. It will cause LoadLibrary to always fail. Either use LoadLibraryW directly and L"" prefix for literal strings if you must pass a Unicode string or use _T() macro and include <tchar.h>.

[julof26]

oh yees, god I hate microsoft and their redefined variable names.
in the tutorial there was only hinstDLL = LoadLibrary("MW.dll"); and it worked but I get the error that I canoot pass char* to LoadLibrary that there must be LPCWSTR so I just used the cast and I forget the L, thank you so much :D