BUG: API Return Code Is Inconsistent in HTML Help

The HTML Help Application Programming Interface (API) does not always return NULL when it fails during an HH_DISPLAY_TOPIC command.

HTML Help uses Internet Explorer to display and access .chm files. If the HTML Help API fails due to the HTML Help control, a NULL will be returned. If the failure is due to Internet Explorer, a NULL will not necessarily be returned.

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

An example of this inconsistency would be the creation of a window with a topic displayed in it. If creating the window fails, a NULL would be returned because this failure occurs in the HTML Help control. If navigating to the window fails, a non-NULL value would be returned because the creation of the window succeeded and the failure came from Internet Explorer.