Back in the days of DOS to Windows when the market was about 60% DOS and 40% Windows (early 1990's) Borland was the first to the market (when compared to Microsoft) with a C++ compiler. Shortly after this compiler came out they also brought out 2 libraries. One was called OWL which stood for Object Windows Library and I forget the name of the other but it might have been TF for Turbo Framework. OWL was a library for writing Windows apps and TF was a windowing library for DOS.
During that period a lot of programmers were trying to target both platforms to maximize the number of platforms their software ran on - an obvious goal and is still in practise today. What I thought was crazy was they fact that OWL and TF had completely unrelated API's. In other words, there was no way you could easily target 2 platforms with this compiler. At the time I thought that it was ludicrous and I've never seen a good explanation for it.
A short while later Microsoft brought out the first of its Visual C++ compilers with MFC (Microsoft Foundation Classes) and walked away with the market. MFC never targeted DOS but by then I believe that the PC market share had reached a 50/50 point and it was obvious that DOS was doomed. Had Borland brought out a single API that could target both systems I believe that they would have survived for many more years in that market and may have even been a competitor today.