Re: [PATCH 0/2] MR7169: ntdll: Fix the return value of NtDelayExecution.

[William Horvath (＠whrvth)]

William Horvath (@whrvth) commented about dlls/ntdll/unix/server.c:
>  /* A test on Windows 2000 shows that Windows always yields during
>     a wait, but a wait that is hit by an event gets a priority
>     boost as well.  This seems to model that behavior the closest.  */
> - if (ret == STATUS_TIMEOUT) NtYieldExecution();
> - if (ret == STATUS_TIMEOUT)
> - {
> -
>    int yield_ret = NtYieldExecution();
> -
>    /* The following should only be reached from NtDelayExecution.
> -
>       It never returns STATUS_TIMEOUT directly, and propagates
> -
>       the result of the yield for zero-timeout waits.
> -
>       Otherwise, it reports STATUS_SUCCESS. */
> -
>    if (!select_op)

I assume the main problem with this patch is due to this check here. While this works correctly for now with how `server_wait` is used, it's just an extra thing to be careful about in the future.

However, the other options I considered also had tradeoffs:
- Add an argument to `server_wait` to signal if we want the return value of the yield (best alternative)
- Just yield again in `NtDelayExecution` itself, ignoring the fact that we already yielded, and return the result there like we do for the non-alertable case (second best alternative)
- Move the yield outside of `server_wait` and duplicate it everywhere `server_wait` is called (terrible)

Maybe there's something else to consider, but the current version isn't so bad if you take these alternatives into account.