I tested that up to date Windows 11 returns STATUS_PARTIAL_COPY / ERROR_PARTIAL_COPY even if none of the range is accessible or remote pointer is NULL. This behaviour matches shortcut path for the same process which we have in NtReadVirtualMemory(). I thought about including a test for it but that is getting messy. There are differences between Windows versions (while none probably returns STATUS_ACCESS_DENIED here, the old variant might be STATUS_ACCESS_VIOLATION), then extensive tests hit different behaviour for ptrace() fallback where the memory is read through page no access protection and workarounds for that make the tests messy and hardly testing anything, so maybe it is fine as is. This helps EA overlay in A Way Out. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10525#note_134556