Re:fork() can fail
by prof_hobart on Thursday August 21, 2014 @04:46AM
(#8206470)
I'm quite liking Swift's optionals.
If it's possible for the call to fail to return an object, you declare its type as optional (add a ? to it) and then the calling code has to explicitly "unwrap" the return value to get to the actual object - they can't simply go
var pid=fork()
pid.kill()
as that would be a compiler error. Instead, they need to go
pid!.kill()
The idea is that they should check for the pid object being nil before doing the unwrapping. Of course, it's still possible for the coder to ignore that (just as it's possible, and depressingly common, for coders to catch and then ignore exceptions), but that's going to be a conscious decision because the compiler is telling them that there's a possible error condition here.
If it's possible for the call to fail to return an object, you declare its type as optional (add a ? to it) and then the calling code has to explicitly "unwrap" the return value to get to the actual object - they can't simply go
as that would be a compiler error. Instead, they need to go The idea is that they should check for the pid object being nil before doing the unwrapping. Of course, it's still possible for the coder to ignore that (just as it's possible, and depressingly common, for coders to catch and then ignore exceptions), but that's going to be a conscious decision because the compiler is telling them that there's a possible error condition here.