alt Hacker News16-bit Windows used the Pascal calling convention, with the documentation in the Windows 1.0 SDK only listing Pascal function declarations. (Most C programs for 16-bit Windows use FAR PASCAL in their declarations—the WINAPI macro was introduced with Win32 as a porting tool.) The original development environment for the Macintosh was a Lisa prototype running UCSD Pascal, and even the first edition of Inside Macintosh included Pascal declarations only. (I don’t know how true it is that Windows originated as a porting layer for moving (still-in-development) Excel away from (still-in-development) Mac, but it feels at least a bit true.) If you look at the call/return instructions, the x86 is clearly a Pascal machine (take the time to read the full semantics of the 80186’s ENTER instruction at some point). Hell, the C standard wouldn’t be out for two more years, and function prototypes (borrowed early from the still-in-development C++, thus the unhinged syntax) weren’t a sure thing. C was not yet the default choice.
>> Also, the stack is restored by the called procedure rather than the caller.
> What could possibly go wrong?
This is still the case for non-vararg __stdcall functions used by Win32 and COM. (The argument order was reversed compared to Win16’s __far __pascal.) By contrast, the __syscall convention that 32-bit OS/2 switched to uses caller cleanup (and passed some arguments in registers).
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The Windows as a porting layer story is a whole subject in its own right. But the WINAPI macro was a porting thing.
But this is an example on this very page of the telephone-game problem that happened during the Operating System Wars, where the porting tool of the WINAPI macro that Microsoft introduced into its DOS-Windows SDK, allowing 32-bit programmers to divorce themselves from the notion of "far" function calls that 16-bit programmers had to be very aware of, becomes intertwined into a larger "Windows is a porting layer" tale, despite the two being completely distinct.
That a couple of applications essentially supplied 16-bit Windows as a runtime really was not related to the 16-bit to 32-bit migration, which came out some while after DOS-Windows was a standalone thing that one ran explicitly, rather than as some fancy runtime underpinnings for a Microsoft application.
* https://jdebp.uk/FGA/function-calling-conventions.html#WINAP...
I don't know if Windows started as a porting layer but it certainly ended up as one. Windows was already on v2.x by the time Excel was released on PC, but the initial PC version of Excel shipped with a stripped-down copy of Windows so that it could still run on machines without Windows. https://devblogs.microsoft.com/oldnewthing/20241112-00/?p=11...