FIX: DDE Warning Message: Invalid Value: -32767

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows version 3.1

SYMPTOMS

When executing a call to DdeClientTransaction() from a Microsoft Foundation Class (MFC) Library application in the debug version of Windows 3.1, the following warning message is displayed in the debug monitor:

   wn  CLIENTAPP  CallNextHookEx + 2C: Invalid value: -32767"

CAUSE

This error message is caused by the _AfxMsgFilterHook hook procedure installed by MFC. This hook procedure, found in line 408 of the file APPCORE.CPP of the MFC source, incorrectly passes internal DDEML messages to the CallNextHookEx() function. When the hook procedure receives a MSGF_DDEMGR message, it should return FALSE instead.

For additional information, please see the following article(s) in the Microsoft Knowledge Base:

   ARTICLE-ID: Q89828
   TITLE     : Do Not Forward DDEML Messages from a Hook Procedure

RESOLUTION

Although this warning message is generally harmless, one way to prevent this message is to modify the _AfxMsgFilterHook function in the APPCORE.CPP file (found in \MSVC\MFC\SRC directory for Microsoft Visual C++ version 1.0) to return FALSE if (code == MSGF_DDEMGR), as the KB article above recommends, and then rebuild the library.

STATUS

Microsoft has confirmed this to be a bug in Microsoft Foundation Classes (MFC) versions 1.0, 2.0, 2.5, 2.51, and 2.52. This problem was corrected in MFC version 2.53, which was included with Visual C++ for Windows version 1.53.