Interrupts / Move most of int31 to winedos

Robert Amstadt bob at
Wed Nov 6 10:37:26 CST 2002

> Sure, I know that (I'm working on DPMI32 which isn't for standard mode
> Windows programs), I was probably being a bit unclear about
> what I was wondering about. It is quite difficult to find any information
> about Win32s nowadays and everything I have found was suggesting that
> Win32s was for running Win32 applications on Win16. Since Wine does run
> Win32 applications directly it just made me wonder whether Win32s support
> is something that was once needed when Wine only had Win16 support.

Win32s was an add-on to Windows 3.1 to allow it to run 32-bit Windows apps 
before Win95 was available.  The "s" in Win32s meant that it was a subset 
of Win32 because features like threading and others simply weren't 
available in Win32s.

I always assumed that the binary interface was the same as the full Win32. 
The add-on DLLs that made up Win32s were supposed to translate the 32-bit 
calls into the equivalent 16-bit calls.  However, knowing Microsoft, I 
could easily be wrong.  I do still have old copies of MSDN and I believe 
that I probably still have an old enough compiler that would produce a 
Win32s program.

All-in-all, I wouldn't spend much (if any) effort on Win32s because it was 
simply intended as a transitional system and didn't really get installed in 
all that many computers.  Most 32-bit apps waited for the arrival of Win95 
before they were released.

Bob Amstadt
bob at

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