On Tuesday, 17 June 2014 at 08:55:52 UTC, bearophile wrote:
Walter Bright:
But it is not uninitialized. All out parameters are default
initialized to their .init value.<
I don't agree with this opinion, as they *are* initialized.<
[...]
void foo(out int x) {}
void bar(out int x) { x = 10; }
[...]
Bye,
bearophile
What if x is an "optional" out parameter: EG: something you only
set if other conditions are met? Do you want to make sure that x
is at least assigned to once, or rather make it an error to have
a control path that *doesn't* assign anything to it.
Either way:
1. Making it an error to have a control path that doesn't assign
to x would be counter productive, as the result would probably
end up being code that looks like:
foo(out int x) {
x = 0;
...
}
which would defeat the entire point of out.
2. Checking the variable is at least used would be kind of the
same as checking for unused arguments. I think that'd be fine,
provided you could over-ride the warning by not naming your
variable:
foo(out int x){} //Error, x is never assigned to (or used)
foo(out int){} //OK!
