https://bugs.winehq.org/show_bug.cgi?id=47379
--- Comment #4 from Carlo Bramini carlo.bramix@libero.it --- Well, I tested Windows XP, Windows 7 (32bit and 64 bit executable) and WINE.
* on Windows XP, I renamed my help file from "calc.chm" to "calc2.chm", just to avoid conflicts with existing file, and I modified temporarily my calculator with the new file name. HtmlHelp functions received the file name as described in the first post and it worked fine.
* on Windows 7, it was a bit easier because the Help directory inside %systemroot% is a bit different: the files are placed in sub-directories, so the temp change made for XP was not needed. Again, I copied the file calc.chm and I tested. It worked fine.
* on WINE, with sources downloaded from GIT, it did not work until I wrote the patch that I have sent into the mailing list.
I could not test other versions of Windows. At the moment, yes, it seems to me and to other people that HtmlHelp() functions resolve environment variables. Perhaps, you may find interesting a test program made by an user for testing the issue here:
https://jira.reactos.org/browse/CORE-15019