Microsoft: Rust Is the Industry’s ‘Best Chance’ at Safe Systems Programming

Re:Microsoft: Rust Is the Industry’s ‘Best Chance’ at Safe S... by bjourne on Saturday June 13, 2020 @04:40PM (#23512505)

Rust doesn't check for numerical over and underflows unless you run in debug mode which almost no one does because it is about two times slower than release mode. I.e. Rust doesn't live up to the safety standards many programmers coming from dynamic languages are used to where over and underflows are checked.

Many people in the Rust community appear to be unaware of this. Which is actually a big deal. Many of the bugs with the most catastrophic consequences are caused by over and underflows. Consider for example a gas pedal indicator kept as an unsigned that underflows causing the indicator to reach its maximum value.

If safety was my primary concern, I wouldn't choose C++ but I wouldn't choose Rust either.

[ Parent | on HN ]

Re:Microsoft: Rust Is the Industry’s ‘Best Chance’ at Safe S... by smitop on Saturday June 13, 2020 @05:33PM (#23512941)

You can pass "-C overflow-checks=on" to rustc to generate an optimized build with over/underflow checks enabled, even in a release build. Also, note that over/underflow behavior is defined to always be two's compliment wrapping when overflow checks are disabled.

[ Parent | on HN ]

Re:Microsoft: Rust Is the Industry’s ‘Best Chance’ at Safe S... by staticassertion on Saturday June 13, 2020 @05:46PM (#23513055)

> Rust doesn't check for numerical over and underflows unless you run in debug mode which almost no one does because it is about two times slower than release mode.

Totally, I wish Rust could express over/underflows better!

> Rust doesn't live up to the safety standards many programmers coming from dynamic languages are used to where over and underflows are checked.

Yeah, that's possible. Thought it won't lead to unsafety, it is definitely a gotcha.

> Many people in the Rust community appear to be unaware of this. Which is actually a big deal.

Maybe, not sure.

> If safety was my primary concern, I wouldn't choose C++ but I wouldn't choose Rust either.

Really depends on the goals and constraints, of course. I'd be really concerned about using rust where an integer overflow could kill someone. I'd be really happy to use rust where a program crashing is totally acceptable, but exploitability isn't.

[ Parent | on HN ]

Re:Microsoft: Rust Is the Industry’s ‘Best Chance’ at Safe S... by acje on Sunday June 14, 2020 @12:04PM (#23518760)

Rust is memory safe, not infallible. Catching more runtime errors is a something rust can improve on. Erlang being one example of a strategy.

[ Parent | on HN ]