If you were designing a standard library of a high level language (like Rust, C++, etc.) what would it do if while getting the current time of day (e.g. SystemTime::now()) it encountered a failed kernel system call (e.g. to clock_gettime) and why?
What do you think the existing implementations do?
- Return error or raise exception
- Return 0
- Return undefined values (like stack garbage)
- Panic/crash/segfault
If that’s the only error mechanism, sure. Exceptions in most languages tend to be relatively expensive, though, and most have a cheaper idiomatic way of returning error codes; you’d want to use those if they’re available, right?
Does Rust use exceptions a lot? I don’t know. V has panic and catch, but you almost never see them. Idiomatic is Option (?) and Return (!) values, which I thought V borrowed from Rust. Go does the (val, error) tuple-ish return thing, and while it too has catchable panics, they’re discouraged in favor of (error) return values.
Depends on the language. “Higher level” is a pretty broad field!
I think not being able to get the current time from the system is very exceptional. And I think exceptional circumstances should act that way and not “look like” normal executions. To me, that means letting hell break loose, and not “silently” return a 1 instead of a 0.
By similar reasoning, “Exceptions in most languages tend to be relatively expensive” is a very weak argument. We don’t expect this error-throwing code to execute a lot.
I can think if plenty of situations where system time is
In fact, if you don’t set up your containers right, the system time is almost always wrong.