July 22, F2F in Boston:

Issue came up when discussing last paragraph of 3.6.1.2:

If the element is an <img> and the text equivalent is empty, then check for the presence of any labeling attribute, specifically aria-label, aria-labelledby, alt or title. The presence of any of these would indicate the author's intention to set an empty text equivalent for decorative or redundant image content. If none of these attributes are present, this indicates the author simply did not provide an accessible label for the image, and the implementation must return the default value of the name property (for example, NULL in MSAA), instead of an empty string. This hints to the AT to do its own heuristic processing, such as accessing the DOM, to repair the missing accessible name.

If API only supports an empty string and not NULL, how does the AT know to fall back to heuristics?

Andi to contact Apple: Does Mac support NULL or only empty string?

Question sent to Apple contacts on January 25, 2010.

Response from Apple: Yes it does support null. Often the API is supposed to return an NSArray or a UIElement reference. in those cases, NULL is acceptable