On Tuesday, 21 August 2018 at 10:57:15 UTC, Atila Neves wrote:
Never mind, I forgot to use -dip1000. Ok, cool, so _why_ does
it work as intended now? Also, if I have to remember to
annotate correctly, surely this is a massive hole in @safe
dip1000?
It thought dip1000 was impenetrable, but if I understand it
(honestly that's a surprise!), `scope` has strict semantics: all
in, nothing out; you don't need to think about lifetime of data
passed to scope parameters, because it doesn't escape anywhere.
If you want to return data extracted from argument, `return`
attribute relaxes scoping rules and allows to return data and
passes scoping properties from argument to return value much like
`inout` does for const.
Without annotation:
@safe:
struct MyStruct
{
import core.stdc.stdlib;
int* ints;
this(int size) @trusted { ints = cast(int*) malloc(size); }
~this() scope @trusted { free(ints); }
inout(int)* ptr() inout { return ints; }
}
int* gInt;
void f()
{
scope s=MyStruct(10);
gInt=s.ptr;
}
Error: scope variable s assigned to non-scope parameter this
calling MyStruct.ptr
Doesn't let to call method without annotation.
