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On Windows GetWriteWatch won't work if the range is not withing a single 
memory view regardless of MEM_LARGE_PAGES (that is, single VirtualAlloc 
result, somewhat analogous to VMA but not quite), such a call will 
result in an error.

For the context, Windows never auto splits or joins memory views, and 
basically nothing can be done across views boundary (merging placeholder 
views is an exception, while unrelated). VirtualProtect (which stands 
for mprotect) can be done for individual pages withing the view of 
course, but it is purely per page and doesn't affect view protection 
flags or result in any splitting of those. VirtualProtect across views 
adjacent in memory will also fail.

On 7/27/23 05:18, Michał Mirosław wrote:
>
> Is it possible (on Windows) to have MEM_LARGE_PAGES allocation near a
> normal one and run GetWriteWatch() on both in one call? If so, how
> does it behave / what is expected?
>
> Best Regards
> Michał Mirosław