Re: pass parameter between main thread and working thread

From:

"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Tue, 1 Apr 2008 10:53:40 -0700

Message-ID:

<713E8A92-3567-490B-BFB0-0D9033F8100A@microsoft.com>

"keith" <keith@discussions.microsoft.com> wrote in message
news:825D91E6-87F8-40CA-80D2-2D84330ADBA3@microsoft.com...

I started a working thread by
AfxBeginThread(ThreadProc, GetSafeHwnd());

In the ThreadProc function, I sent a user message
::PostMessage((HWND)pParam, WM_THREADFINISHED, 0, 0)
when it is done and a main thread function handles the message.

note: WM_THREADFINISHED is user defined message.

The problem is how to pass parameter from main thread to the working
thread
and vice versa.

I can do it to pass parameter to working thread by
CString c("abc");
AfxBeginThread(ThreadProc,(LPVOID)&c);

But main thread function cannot receive the user message.

You only have one pointer-sized parameter you can pass to the thread proc,
so you have two choices...

1) Pass a pointer to an object that has all the info the thread needs
(recommended)
2) Use global variable(s) - all threads have access to those (not
recommended)

In this case, since the thread is created from the window that is to receive
the finished message, I would pass a pointer to the window object, and in
the window class, provide whatever methods are needed for the thread to get
the required parameters from the window class through the passed window
object pointer.

Hopefully that made sense :)

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++

Do you have any way to pass parameters?

Thanks