Re: cast problem

From:
"mlimber" <mlimber@gmail.com>
Newsgroups:
comp.lang.c++
Date:
16 Jun 2006 11:25:13 -0700
Message-ID:
<1150482313.710217.59510@u72g2000cwu.googlegroups.com>
cdg wrote:

I am trying to write a section of code that uses a worker thread and
would need a "post message" to post a
"long" integer to the receiving function. However, I am not sure how to
write the cast for the "long" int. Apparently,
the "long" needs to be a pointer since the thread was passed the "this"
pointer for the main dialog. And the "long" is declared in the main dialog
class. If it is declared as a local variable, there is an Assertion Error
after the program is compiled, and a "Start" button is pushed. This button
starts the thread.

   So, could anyone correctly write the "cast" statement that would be
needed for this post message. My C++ is not that versatile yet. And I'm
still learning how to use pointers and cast in most situations.

-----------------------------------------
error C2440: 'type cast' : cannot convert from 'long CThreadTestDlg::*' to
'long'
-----------------------------------------

The worker thread section of code:

UINT CThreadTestDlg::Thread1(LPVOID lParam)
{
 CThreadTestDlg* pDlg = (CThreadTestDlg *)lParam;

ActxPrg m_ActxPrg; //object declaration

 m_ActxPrg.Open(); // open ActxPrg

 lResult = m_xActxPrg.MemFunction();

 m_ActxPrg.Close(); // close ActxPrg

 pDlg->PostMessage(UWM_THREAD_FINISHED, (WPARAM)0, (LPARAM) lResult);

 return 0;
}


You don't give us all the information we need. Where is the error
happening? On which line, and if it's on the PostMessage call, what are
the types that PostMessage() expects, and what is the type of each of
the identifiers on that line?

Please note that we don't deal with threading issues here because they
are not (yet) part of Standard C++ language and libraries. For that
reason, you may want to post in a group more applicable to your
platform or compiler. See this FAQ for what is on-topic here and for a
list of possible other groups:

http://www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.9

Cheers! --M

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