previous: >>108813613
#define __NR_timer_create 222
#define __NR_timer_settime 223
#define __NR_timer_gettime 224
#define __NR_timer_getoverrun 225
#define __NR_timer_delete 226
https://man7.org/linux/man-pages/man2/timer_create.2.html
https://man7.org/linux/man-pages/man2/timer_delete.2.html
https://man7.org/linux/man-pages/man2/timer_settime.2.html
https://man7.org/linux/man-pages/man2/timer_getoverrun.2.html
tl;dr:
manage posix timers
similar to the clock syscalls we've discussed before, except these can be armed and fire after a given amount of time has elapsed.
not part of the vdso, so far as i can tell, which is a bit surprising! you'd expect something like this to fit into there nicely. i guess the idea is you're not constantly polling it like you are a clock? so it's only expected to be accessed when you create/destroy, arm/disarm, and when it fires
i won't ask if people have used this before, because this is the sort of thing that gets used all the time by everyone. what i will ask is what's the most obscure clock type you've had occasion to use, and what were the circumstances?
relevant resources:
man man
man syscalls
https://man7.org/linux/man-pages/
https://linux.die.net/man/
https://elixir.bootlin.com/linux/
https://elixir.bootlin.com/musl/
https://elixir.bootlin.com/glibc/
