Each Windows AIO request is an overlapped ReadFile/WriteFile at the
request's offset, which on a synchronous handle also moves the
descriptor's file pointer; on the console AIO transfers leave it alone.
The requests now go through the positioned path sceKernelPread and
sceKernelPwrite use (NativePositioned in Stdio.cpp, exposed as
NativePositioned_nid_no_patch), which restores the pointer afterwards.
Negative offsets still fail with EINVAL before the transfer.
GuestAio sets the offset to 2 before a write batch and checks it is
still 2 after. TechnicalDebt records that a concurrent read or write on
the same descriptor can see the moved pointer in between, as for the
pread family.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UTjpbMX7BUFMZZaxJE98zV
On Windows each AIO request seeked a _dup of the descriptor and then read
or wrote through it. A duplicated descriptor shares the file position, and
the seek and the transfer are separate calls, so two threads submitting
requests on one descriptor could transfer at each other's offset. Each
request is now a single ReadFile/WriteFile with an OVERLAPPED offset on
the OS handle, as pread and pwrite already do in Stdio.cpp.
GuestAio reads four distinct blocks of one descriptor from four threads
and checks every result.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HeC9bA3n74TzJRYv9AgBE8
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