Just decided to do a bit of archaeology.<p>The macros in the Windows 3.1 SDK were the strict header mode and message crackers.<p><a href="https:&#x2F;&#x2F;support.microsoft.com&#x2F;en-us&#x2F;kb&#x2F;83456" rel="nofollow">https:&#x2F;&#x2F;support.microsoft.com&#x2F;en-us&#x2F;kb&#x2F;83456</a><p>It made my life sane every time I had to use C instead of C++, and yet very few people knew about them.<p>Petzold never mentioned them in his books, I discovered them by chance in another book.<p>Nice to know that the Afx story might have not been a rumour, since other people heard the same.<p>My first Visual C++ was v5.0, by then it was already clear that Borland was on they way out as first choice. Sadly.