NtCancelIoFileEx function is missing

[kennykerr]

The function is documented here:

https://learn.microsoft.com/en-us/windows/win32/devnotes/nt-cancel-io-file-ex

It seems like this should be included as it is clearly for desktop use and the Win32 metadata includes various other functions exported from ntdll.dll. I'm just not sure where to find the header.

Originally posted by @Thomasdezeeuw in tokio-rs/mio#1632 (comment)

[KalleOlaviNiemitalo]

Is the documentation correct in that NtCancelIoFileEx returns BOOL? I'd expect Nt functions to return NTSTATUS.

[Thomasdezeeuw]

Is the documentation correct in that NtCancelIoFileEx returns BOOL? I'd expect Nt functions to return NTSTATUS.

Mio has been handling it as a NTSTATUS and it hasn't blow up yet (https://github.com/tokio-rs/mio/blob/fc2080cd0a663125b59f0afa2bc1c771a3fbec1e/src/sys/windows/afd.rs#L28).

[kennykerr]

Yes, the docs are not correct either. 😜

[KalleOlaviNiemitalo]

Huh so there is a third parameter as well.

Anyway, why would an application call NtCancelIoFileEx rather than the better-documented CancelIoEx? Does win32metadata attempt to support native NT (not Win32) applications?

[mikebattista]

Is this header in the WDK? I don't see it in the SDK.

[kennykerr]

I haven't been able to find a public version of it.

[Thomasdezeeuw]

Huh so there is a third parameter as well.

Anyway, why would an application call NtCancelIoFileEx rather than the better-documented CancelIoEx? Does win32metadata attempt to support native NT (not Win32) applications?

Because we use the third argument: https://github.com/tokio-rs/mio/blob/fc2080cd0a663125b59f0afa2bc1c771a3fbec1e/src/sys/windows/afd.rs#L119. Although I'm too familiar with Windows. Perhaps this can be rewritten to use CancelIoEx? For context wepoll also uses NtCancelIoFileEx: https://github.com/piscisaureus/wepoll/blob/0598a791bf9cbbf480793d778930fc635b044980/wepoll.c#L404-L405.

[elachlan]

Related: #1, #3, #6, #7, etc.

[kennykerr]

Just following up on this issue. I can't find the public header with it but since it is documented here's the correct definition:

NTSTATUS
NTAPI
NtCancelIoFileEx(
    _In_ HANDLE FileHandle,
    _In_opt_ PIO_STATUS_BLOCK IoRequestToCancel,
    _Out_ PIO_STATUS_BLOCK IoStatusBlock
    );

Perhaps we can manually include it in the WDK metadata along with all of the other NtXxx APIs that are now present.