On Monday, November 25, 2019 1:32:53 AM MST H. S. Teoh via Digitalmars-d- learn wrote: > On Mon, Nov 25, 2019 at 08:07:50AM +0000, Fanda Vacek via > Digitalmars-d-learn wrote: [...] > > > But anyway, pointers are not allowed in @safe code, so this is not > > always solution. > > [...] > > This is incorrect. Pointers *are* allowed in @safe code. Pointer > *arithmetic* is not allowed.
That and taking the address of a local variable is @system, though with -dip1000, it becomes @safe by making the result scope, which restricts what you can do with it. And of course, @trusted can be used where appropriate to make it so that @system code can be used from @safe code, though obviously, that means that it's up to the programmer to make sure that they verify that what the @trusted code is doing is actually @safe. Further, with regards to taking the address of a local variable being @system, ref would be @system for exactly the same reasons save for the fact that there are various restrictions in place to ensure that it can't be used in a manner which would allow the underlying pointer to exist longer than the address that it refers to. Allowing variables in general to be declared as ref instead of only allowing it in restricted circumstances such as function parameters and return types would put ref in the same @system quagmire that exists with regards to taking the address of a local variable. By restricting ref, that problem is avoided, whereas pointers still allow for full freedom but in return, they require that certain operations that relate to them be @system (like &, ++, and --). - Jonathan M Davis
