- The window class in the DLL was not registered correctly with the CS_GLOBALCLASS class style. Without this class style, a class cannot be accessed globally by all the applications that link into the DLL. -or-
- The DLL is not loaded into memory and therefore the class is not accessible. This will happen if the application implicitly links to the DLL, and none of the exported functions in the DLL is explicitly called in the application. To work around this problem, the DLL must provide an entry point for the application to call or the application must explicitly load and free the library.
Care must be taken to ensure that an application global class is not accessed after the DLL (that registered it) terminates. Doing so will generate a Fatal Exit 0x001A message under the debug version of Windows. For more information on this topic, query on the following words in the Microsoft Knowledge Base:
Also, note that with Windows version 3.0, there is a potential problem in destroying windows whose window class has been registered with the CS_GLOBALCLASS class style by a DLL (or an application). This problem has been corrected in Windows version 3.1. For more information on this problem and a solution, please query on the following words in the Microsoft Knowledge Base:
Article ID: 97758 - Last Review: Oct 30, 2003 - Revision: 1