Appears to be missing asReleaseExclusiveLock() in the case (it == stringCache.end()) line 73.

Maybe I'm misinterpreting how the exclusive lock works, though.

I think you misread the code. The function doesn't exit in case (it == stringCache.end()) on line 73. It will just set the variable ret to asERROR, and then proceed on line 82 where it calls asReleaseExclusiveLock() and only after that return from the function.

I sure did misread it. I have a wide string version of the file I made from the previous version, and when I updated it to your latest version I missed the added return value. Sorry to waste your time.