[1/2] ntdll: Properly handle 0-length reads.

[Dmitry Timoshkov]

Marvin <testbot at winehq.org> wrote:

> === wxppro (32 bit comm) ===
> comm.c:863: Test failed: WaitCommEvent failed with a timeout
> comm.c:875: recovering after WAIT_TIMEOUT...
> comm.c:886: Test failed: WaitCommEvent error 0
> comm.c:888: Test failed: WaitCommEvent: expected EV_TXEMPTY, got 0
> comm.c:892: WaitCommEvent for EV_TXEMPTY took 1000 ms (timeout 1000)
> comm.c:894: Test failed: WaitCommEvent used 1000 ms for waiting
> 
> === w7pro64 (32 bit comm) ===
> comm.c:863: Test failed: WaitCommEvent failed with a timeout
> comm.c:875: recovering after WAIT_TIMEOUT...
> comm.c:886: Test failed: WaitCommEvent error 0
> comm.c:888: Test failed: WaitCommEvent: expected EV_TXEMPTY, got 0
> comm.c:892: WaitCommEvent for EV_TXEMPTY took 1014 ms (timeout 1000)
> comm.c:894: Test failed: WaitCommEvent used 1014 ms for waiting
> comm.c:1561: test_AbortWaitCts timeout 500 handle 000000F8
> comm.c:1528:  Changing CommMask on the fly for handle 000000F8 after timeout 500

These failures have nothing to do with this patch.

-- 
Dmitry.