asked on

Serial Communications

Hi

I am re-jigging some code I have used for some time now and have hit a small
problem.

I have two apps using the same serial comm code. On a call to

OnSerialMsg in the new app I am building

The debugger keeps bringing up the file

C\...\SRC\Intel\CHKSTK.ASM

File Header....

page ,132
title chkstk - C stack checking routine
;***
;chkstk.asm - C stack checking routine
;
; Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.
;
;Purpose:
; Provides support for automatic stack checking in C procedures
; when stack checking is enabled.

End File Header

Then as soon as it hits any one of the if statements the debugger jumps to
return 0 and exits the function. I have debugged this code many times
and have never had this happen

LRESULT CSerialDlg::OnSerialMsg(WPARAM wParam, LPARAM /*lParam*/)
{
      CSerialAPI::EEvent eEvent = CSerialAPI::EEvent(LOWORD(wParam));
      CSerialAPI::EError eError = CSerialAPI::EError(HIWORD(wParam));

      if (eError)
            // what a do?

      if (eEvent & CSerialAPI::EEventBreak)


      if (eEvent & CSerialAPI::EEventError)


      if (eEvent & CSerialAPI::EEventRcvEv)

....................

return 0;
}

Any help much appreciated

LittlePerson

Member_2_1001466

An error during stack checking normally means that calling conventions don't match. Possible ones are __cdecl, __stdcall or PASCAL. The difference is how they treat arguments to functions: Putting them from left to right or the other way on the stack and who has to cleanup when the function finishes. If the stack is not cleaned up by the called function as the calles expected you will get this error. But writing out of bounds of an array might modify the stack in a way that a check fails on return.

Standard for C/C++ is __cdecl which means right to left pushing of arguments. Callee must clean the stack.

LittlePerson

ASKER

I am not understanding !!!

ASKER CERTIFIED SOLUTION

Member_2_1001466

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LittlePerson

ASKER

Thanks for the replies.

I will post more code later as time is tight at the moment. The only change I made
is that instead of writing CString* over the serial communication I am now sending
an unsigned char.

Till later...

Thanks

LittlePerson

ASKER

Thanks again for the reply and sorry for the delay in getting
back to the question. Fortunately the code is performing OK now
(well I have a new problem now - new question to be posted)

Hopefully you can help with this new problem.

Regards
LittlePerson