AfxBeginThread() with a function in the main class

Johpoke

This is allways something wich i have had trouble with, usualy i end up doing some ugly trick to make it work.. But this time i cant.. (well ive been spending around 3 days trying..) I need a thread which is connected to the main class of my MFC Dialog based application. I looked at Code Project:Using AfxBeginThread...[^] In which i end up createing a new static function that seems to work with some functions.. But when i tried calling the function i wanted it to run, it couldnt since it wasnt a static function.. So i tried making it a static function, but then i got loads of error messages... So how would i go about creating and running a thread that is connected to the main class (like "CThreadDemoDlg::OnStart()" ) ? The function doesnt need any params or other advanced features, maybe i should start it using a differnt function? Or how should i go about this? thanks! PS: Im not really that good at the terminology for c++, or c++ programming itself, so nothing too hightech or advanced unless its a must do..

//Johannes

led mike

Well this is not a MFC thread but it can work in MFC applications and/or maybe it will help give you the idea

/** Win32 CreateThread class wrapper */
class base_w32thread{
protected:
    HANDLE    _handle;
    DWORD    _dwTID;
    base_w32thread():_handle(0), _dwTID(0L){}
    virtual ~base_w32thread()=0;

public:
    bool start(LPSECURITY_ATTRIBUTES psecattrs = NULL, DWORD dwCreateFlags = 0L);
    operator HANDLE(){ return _handle; }
protected:
    virtual void run()=0;
    virtual void onEndThread(){}
    static long WINAPI threadfnc( LPARAM lp);
};

#include "StdAfx.h"

#include "base_w32thread.h"
#include <winbase.h>
#include <assert.h>

base_w32thread::~base_w32thread(){}

/** start the thread */
bool base_w32thread::start(LPSECURITY_ATTRIBUTES psecattrs, DWORD dwCreateFlags){

assert( !_handle);
if( _handle)
return false;

_handle = ::CreateThread( psecattrs, 0,
(LPTHREAD_START_ROUTINE)threadfnc, this, dwCreateFlags, &_dwTID);
return (_handle)?true:false;
}
/** Thread function */
long WINAPI base_w32thread::threadfnc( LPARAM lp){

assert( lp);
    base_w32thread* pThis = (base_w32thread*)lp;
    if( pThis)
        pThis->run();

pThis->_handle = 0L;        // thread exited
    pThis->onEndThread();
    return 0L;
}

David Crow

What's wrong with:

void CMyDlg::Process( void )
{
// do whatever you need to in this non-static method
}
...
/* static */ UINT CMyDlg::Process( LPVOID pParam )
{
CMyDlg *pDlg = (CMyDlg *) pParam;

pDlg->Process();

return 0;

}
...
AfxBeginThread(Process, this);

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Mark Salsbery

The thread procedure accepts a void pointer which you can pass when you create the thread. If you pass a pointer to an object of a class then you will have access to that object from the thread. If the thread proc is a static member function of that class, you have complete access (to public/protected/private members).

class CThreadDemoDlg : public CDialog
{
static UINT __cdecl MyThreadProc(LPVOID pParam);
protected:
CWinThread *pAnotherThread;
public:
void SomeThreadStarterFunc();
};

void CThreadDemoDlg::SomeThreadStarterFunc()
{
pAnotherThread = AfxBeginThread(&CThreadDemoDlg::MyThreadProc, this);
}

UINT __cdecl CThreadDemoDlg::MyThreadProc(LPVOID pParam)
{
CThreadDemoDlg *pMyDlg = (CThreadDemoDlg *)pParam;

...
}

Mark

Last modified: 25mins after originally posted --

Mark Salsbery Microsoft MVP - Visual C++ :java:

Johpoke

Thank you all for you great replies :) Im trying out Mark's code right now, but its giving me an error message i really dont understand.. On this line: CThreadDemoDlg *pMyDlg = (CThreadDemoDlg *pParam); error C2146: syntax error : missing ')' before identifier 'pParam' error C2059: syntax error : ')' Ive renamed all the classes to the class on my program, so its not that... What could this be? Thank you all! :)

//Johannes

Mark Salsbery

Fixed. Sorry about that :) It should be

CThreadDemoDlg *pMyDlg = (CThreadDemoDlg *)pParam;

Mark Salsbery Microsoft MVP - Visual C++ :java:

Johpoke

Ah yes now it compiles, thanks. But when i add a function to it (one that is connected to CThreadDemoDlg) i get the cant call a nonstatic member function.. error C2352: 'CThreadDemoDlg::SomeFunction' : illegal call of non-static member function see declaration of 'SomeFunction' So how should i go about calling the function? thanks again!

//Johannes

David Crow

Johpoke wrote:

So how should i go about calling the function?

Can you at least bother to show the code that is producing this error? :rolleyes:

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Johpoke

Doh, UINT __cdecl CThreadDemoDlg::MyThreadProc(LPVOID pParam) { CThreadDemoDlg *pMyDlg = (CThreadDemoDlg *)pParam; MyFunction(); return 1; } It looks exactly like that, except the names are different

//Johannes

David Crow

Hint: Ever wonder what pMyDlg is being used for?

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

led mike

Johpoke wrote:

but its giving me an error message i really dont understand..

You don't understand a syntax error message but you are working with multi threading *sigh* different day same old garbage

Johpoke

I was thinking i must use it to gain access to the rest of the functions so i like tried :: on it but that didnt work. Now i tried -> on it and all my functions come up :D Thanks alot for the help. The only downside with this is im probably gonna have to go through loads of old programs and get rid of their ugly methods and add this. But i guess its worth it :-D Thanks again :)

//Johannes

Mark Salsbery

led mike wrote:

*sigh* different day same old garbage

This[^] should cheer you up. :beer:

Mark Salsbery Microsoft MVP - Visual C++ :java:

led mike

Good Grief :sigh: Happy Friday :beer: :jig:

Johpoke

lol, that dancing dude is funny/weird. My program now works perfectly, thank you all for you help. How does one make that dude anyway? i cant find him...

//Johannes

led mike

Johpoke wrote:

My program now works perfectly

If it works, do it.

If it works, do it it works

seems to work      probably
     ^                  ^
If it   works, do it it    works

(and might work again)

Cogito ergo sum

(although, admittedly, that is an assumption)

Mark Salsbery

:beer:

Mark Salsbery Microsoft MVP - Visual C++ :java:

Mark Salsbery

Johpoke wrote:

How does one make that dude anyway? i cant find him...

It's right next to the :beer: one. With a little ingenuity, you'll find it :)

Mark Salsbery Microsoft MVP - Visual C++ :java:

Johpoke

Maybe its like a gold-member only emotion. or maybe it doesnt like me... Ah well doesnt matter im happy anyway :)

//Johannes

Mark Salsbery

Johpoke wrote:

Maybe its like a gold-member only emotion.

Nope. I was so proud when I found it all by myself, since I know nothing about web programming :) ;P

Mark Salsbery Microsoft MVP - Visual C++ :java: