[int0x29]

There is now at least one public windows kernel call listed on MSDN: __fastfail

https://learn.microsoft.com/en-us/cpp/intrinsics/fastfail?vi...

[quotemstr]

I'd call that a special ABI feature, not a stable system call. Note that it's a software interrupt, not a regular SYSENTER. But sure. Maybe I'm splitting hairs.