4 ms·

` fn do_work_and_then(func: fn(i32)) { thread::spawn(move || { // Figuring out the meaning of life... thread::sleep_ms(1000

by valand 6y ago

` fn do_work_and_then(func: fn(i32)) { thread::spawn(move || { // Figuring out the meaning of life... thread::sleep_ms(1000); // gee, this takes time to do... // ah, that's it! let result: i32 = 42; // let's call the `func` and tell it the good news... func(result) }); } ` you missed a snippet, a thread is spawned. edit: formatting

imtringued 6y ago
If for some magic reason thread::sleep_ms(1000) takes longer than 2000ms the main function would reach its end and deallocate the closure that is about to get called. Basically use after free.
- richardwhiuk 6y ago
  And that's possible, because the sleep call is a suggestion, not a guarantee. If the CPU is blocked for 2s, then the order of waking the threads is undetermined, and the race will occur.
  - deleted 6y ago
    [deleted]
- mav3rick 6y ago
  That is technically a race (sure) but at that point the program is getting killed anyway. Agree on the overall point though. I am a big fan of moving complete ownership / lifetime. It just makes things easier to reason about. In Chromium weak pointers are used to solve this use after free problem.