28390ce4aa
Snippet [22] was unused and the example using snippet [21] neglected to show how its oldCategoryFilter got initialized, which is what [22] does. But it turns out the example code was crashy in any case, as it left the oldCategoryFilter uninitialized (albeit probably null) until the call to installFilter() had returned, and installFilter() calls the new filter, so the new filter needs to check oldCategoryFilter before calling it. The doc also failed to explain why it's OK to not defer to the prior filter in these calls during installFilter(), so revise the doc and example so that the latter behaves sensibly and readers of the former are likely to use the function safely. This amends commit 8f0654ceb878b6c8a08c7f5b790027c26e007c13 which added the snippets and the use of one of them, but not the other. Fixes: QTBUG-49704 Change-Id: Iddb8d97b0bef417d8f16e7910730cfa59ea3e715 Reviewed-by: Kai Koehne <kai.koehne@qt.io> (cherry picked from commit 6ae2bfad411faf896fdca83a55db1e24a0b70e73) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>