Need Help in VC++ Threading

Hi,

I need help regarding VC++ Threading
Here is my piece of code:

Code:

---


CWinThread* thread=NULL;

thread= AfxBeginThread( LoadData(), this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED  );
thread->m_bAutoDelete = false;
thread->ResumeThread();

SUL_WaitForEndOfThread( thread->m_hThread );

---

I am getting access violation error in "SUL_WaitForEndOfThread( thread->m_hThread );"
When my compiler reaches "thread->ResumeThread();" it doesn't call LoadData().
Instead it moves to the next statement SUL_WaitForEndOfThread( thread->m_hThread ); and throws me a access violation error.

Need help in this. :)

Reagrds

1. What is SUL_WaitForEndOfThread?
2. What is LoadData? Why and how is it supposed to be called?
3. What exactly gets this "access violation error": the compiler or your application?

My SUL_WaitForEndOfThread() contains the following:

Code:

---

void  SUL_WaitForEndOfThread( HANDLE hThread )
{

        DWORD                appThreadID = AfxGetApp()->m_nThreadID;
        DWORD                threadID = AfxGetThread()->m_nThreadID;
        DWORD                result;
        int count = 20;


        if ( appThreadID == threadID )
        {
                SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread"), hThread );

                MSG* pMsg = &AfxGetThread()->m_msgCur;
                count = 100;
                while ( TRUE )
                {
                        result = ::WaitForSingleObject( hThread, 0 );
                        if ( count == 100 )
                        {
                                switch ( result )
                                {
                                case WAIT_ABANDONED:
                                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread - WAIT_ABANDONED - %d"), hThread, result );
                                        break;
                                case WAIT_OBJECT_0:
                                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread - WAIT_OBJECT_0 - %d"), hThread, result );
                                        break;
                                case WAIT_FAILED:
                                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread - WAIT_FAILED - %d"), hThread, result );
                                        break;
                                case WAIT_IO_COMPLETION:
                                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread - WAIT_IO_COMPLETION - %d"), hThread, result );
                                        break;
                                case WAIT_TIMEOUT:
                                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread - WAIT_TIMEOUT - %d"), hThread, result );
                                        break;
                                default:
                                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from main thread - %d"), hThread, result );
                                        break;
                                }
                                count = 0;
                        }
                        count++;
                        if ( result != WAIT_TIMEOUT )
                        {
                                break;
                        }
                        if ( ::PeekMessage( pMsg, NULL, NULL, NULL, PM_REMOVE ) )
                        {
                                if ( !AfxGetThread()->PreTranslateMessage( pMsg ) )
                                {
                                        ::TranslateMessage( pMsg );
                                        ::DispatchMessage( pMsg );
                                }
                        }
                        else
                        {
                                Sleep( 50 );
                        }
                }
        }
        else
        {
                SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread"), hThread );
                while ( ( result = ::WaitForSingleObject( hThread, 50 ) ) == WAIT_TIMEOUT )
                {
                        if ( count == 20 )
                        {
                                SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - WAIT_TIMEOUT - %d"), hThread, result );
                                count = 0;
                        }
                        count++;
                        Sleep( 100 );
                }
                switch ( result )
                {
                case WAIT_ABANDONED:
                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - WAIT_ABANDONED - %d"), hThread );
                        break;
                case WAIT_OBJECT_0:
                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - WAIT_OBJECT_0 - %d"), hThread );
                        break;
                case WAIT_FAILED:
                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - WAIT_FAILED - %d"), hThread );
                        break;
                case WAIT_IO_COMPLETION:
                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - WAIT_IO_COMPLETION - %d"), hThread, result );
                        break;
                case WAIT_TIMEOUT:
                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - WAIT_TIMEOUT - %d"), hThread, result );
                        break;
                default:
                        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - from background thread - %d"), hThread, result );
                        break;
                }
                //::WaitForSingleObject( hThread, INFINITE );
        }

        SUL_Log( 5, -1, _T("SUL_WaitForEndOfThread( %d ) - end"), hThread );
}

---

LoadData() is the thread function to be called once a thread is created. It contains the block of code to be executed for some operations.

The compiler gives me this Access Violation Error.

Quote:

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Originally Posted by p_zshk

...
The compiler gives me this Access Violation Error.

---

In what line of your code?

"while ( ( result = ::WaitForSingleObject( hThread, 50 ) ) == WAIT_TIMEOUT )"

this line gives me the Acess Violation.

This your call of AfxBeginThread is wrong:

Quote:

---

Originally Posted by p_zshk

Hi,
Here is my piece of code:

Code:

---

thread= AfxBeginThread( LoadData(), this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED  );

---

---

The correct one is

Code:

---

thread= AfxBeginThread( LoadData, this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED  );

---

oops...done a typo error here...sorry for that...

i have written the syntax the proper way...
thread= AfxBeginThread( LoadData, this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED );

may be there is some other problem...

Show us your LoadData signature

Here is the declaration:

Code:

---

static UINT LoadData( LPVOID aParam );

---

Actually I can't see any reason to create the thread suspended as long as you resume it immediately. So try to get rid of the stuff and see if your problem went off.

I am setting m_bAutoDelete to false, that's why I am creating a thread in suspended mode and then starting the thread through ResumeThread().

Well, if you don't start a thread in suspended mode (and don't call ResumeThread) does the problem persist?

If Yes - create a small project reproducing this behaviour and post it (in zip archive) to the Forum.

Quote:

---

I am setting m_bAutoDelete to false, that's why I am creating a thread in suspended mode and then starting the thread through ResumeThread().

---

You never need to suspend thread for this.

Quote:

---

m_bAutoDelete

Specifies whether to destroy the object at thread termination.

---

It has nothing to do with the thread, it's just about CWinThread object, and nothing more than this.