Question

Not sure what is wrong with parameter 3 or the setup?

error C2440: 'type cast' : cannot convert from '' to 'unsigned long (__stdcall *)(void *)'
        None of the functions with this name in scope match the target type

—

void CNumbergeneratorDlg::OnBtn3()
{
    //CreateThread
    hThread1 = CreateThread(NULL, 0, Thread1, this, 0, NULL);//<--is "this" correct

    WaitForSingleObject(hThread1,INFINITE);
    TerminateThread(hThread1,0);
    CloseHandle(hThread1);
}

DWORD WINAPI CNumbergeneratorDlg::Thread1(LPVOID iValue)
{
    CreateNumber();
    return 0;
}

---

??? casting for “this”

DWORD WINAPI CNumbergeneratorDlg::Thread1(LPVOID iValue)
{
    (CDialog)iValue->CreateNumber();
    return 0;
}

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This is what I did with your guys input… thanks

    void CNumbergeneratorDlg::OnBtn3()
{
    //CreateThread
    CNumbergeneratorDlg *pp = this;
    hThread1 = CreateThread(NULL, 0, Thread1, pp, 0, NULL);

//  WaitForSingleObject(hThread1,INFINITE);
//  TerminateThread(hThread1,0);
//  CloseHandle(hThread1);
}

DWORD WINAPI CNumbergeneratorDlg::Thread1(LPVOID iValue)
{
    CNumbergeneratorDlg *pp = (CNumbergeneratorDlg*)iValue;

    pp->CreateNumber();
    return 0;
}

void CNumbergeneratorDlg::CreateNumber()
{
    long m;
    j = 0;
    for(long i = 0; i < 1000;i++){
        m = 0;
        for(long k = 0; k < 1000000;k++){
            m ++;
        }

        j++;
    }

    AfxMessageBox("Done count");
    TerminateThread(hThread1,0);
    CloseHandle(hThread1);
}

void CNumbergeneratorDlg::OnBtn4()
{

    TerminateThread(hThread1,0);
    CloseHandle(hThread1);

    CString c;
    c.Format("%d", j);
    MessageBox(c);
}

Answer 1

Did you declare the function Thread1 as a static member function in CNumbergeneratorDlg? If not, please do so.

Non-static class functions have an implicit additional parameter for this. So, type casting will not work. On the other hand, static methods do not carry this parameter.

Then, you might wonder how you can access class members inside Thread1. A typical technique is passing this via iValue.