PRB: BroadcastSystemMessageA Not Found in User32.dll on Win 95

• Microsoft Win32 Software Development Kit (SDK) on the following platform:

  - Windows 95

• Microsoft Visual C++, 32-bit Edition, versions 4.0, 4.1, 4.2, 5.0
• Microsoft Win32 Application Programming Interface (API)

SYMPTOMS

If you use BroadcastSystemMessage() in an application written with Visual C++ 4.x or 5.x or the Platform SDK, the application fails on Windows 95 with the following error:

   BroadcastSystemMessageA not found in User32.dll.

CAUSE

The Winuser.h file included with Visual C++ 4.x and 5.x and the Platform SDK defines BroadcastSystemMessage as BroadcastSystemMessageA if UNICODE is not defined. Because Windows NT 4.0 exports BroadcastSystemMessage and BroadcastSystemMessageA as the same ordinal, this works as expected. Because Windows 95 does not export BroadcastSystemMessageA, the run-time bind to User32.dll fails and the application is aborted.

RESOLUTION

In Winuser.h, change the #define that reads:

   #define BroadcastSystemMessage  BroadcastSystemMessageA

   #define BroadcastSystemMessage  BroadcastSystemMessage

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

You can reproduce this problem by creating a dialog-based MFC application and placing the following code in InitInstance (replacing "TODO: Place code here to handle when the dialog is dismissed with OK"):

   BroadcastSystemMessage(BSF_POSTMESSAGE,BSM_ALLCOMPONENTS,WM_NULL,0,0);