Yes if you’re naming it @ccall, that should just be different syntax for ccall.
It looks like disable_sigint far predates @yuyichao’s big cleanup of the interrupt delivery in https://github.com/JuliaLang/julia/pull/16174. I’m not sure disable_sigint is even necessary anymore.
A signal generated (for example) by Ctrl-C can be delivered even in a single threaded, single-Task environment — it’s a facility provided by the operating system (and a bit platform dependent, see https://linux.die.net/man/2/signal or signal | Microsoft Learn for example).
Julia installs signal handlers for various internal things which users normally shouldn’t need to worry about, and from the look of the way InterruptException is now delivered you shouldn’t need to worry about these corrupting the state of code which you’ve ccall’d.