Right (on x86-32 and -64, because you can’t have 64KB pages there, though larger page sizes do exist and get used). You still cannot (e.g.) MapViewOfFile() on an address not divisible by 64KB, because Alpha[1]. As far as I understand, Windows is mostly why the docs for the Blink emulator[2] (a companion project of Cosmopolitan libc) tell you any programs under it need to use sysconf(_SC_PAGESIZE) [aka getpagesize() aka getauxval(AT_PAGESZ)] instead of assuming 4KB.
TIL about MapViewOfFile3 and NtMapViewOfSectionEx, thanks! Still, the Microsoft docs say[1]:
> [in, optional] BaseAddress
> The desired base address of the view (the address is rounded down to the nearest 64k boundary).
> [...]
> [in] Offset
> The offset from the beginning of the section.
> The offset must be 64k aligned.
The peculiar part is where base address and offset must be divisible by 64K (also referred to as the “allocation granularity”) but the size only needs to be divisible by the page size. Maybe you’re right and the docs are wrong?..
[1] https://devblogs.microsoft.com/oldnewthing/20031008-00/?p=42...
[2] https://github.com/jart/blink/blob/master/README.md#compilin...