Casting in Safe D

[Jonathan M Davis via Digitalmars-d-learn]

On Wednesday, November 26, 2014 16:27:53 David Held via Digitalmars-d-learn wrote:
> On 11/23/2014 3:12 PM, anonymous wrote:
> > [...]
> > And even pointer dereferencing is @safe. Invalid ones will fail
> > with a segfault at run time:
> > void foo(int* a) @safe {*a = 13;}
>
> Hmm...throwing an exception is a well-defined behavior, but is
> segfaulting a well-defined behavior of correct D programs?  This seems
> like a peculiar definition of "safe" to me...

@safe is about guaranteeing that memory will not be corrupted and that any
memory that's accessed has not been corrupted. Segfaults don't corrupt
memory and don't allow you to access corrupted memory. Rather, it's the OS
catching that your program has accessed memory that it shouldn't and then
essentially killing your program. The OS is _preventing_ any possible
memory corruption. So, as much as robust programs shouldn't segfault,
segfaults are perfectly safe with regards to memory - which is what @safe is
all about.

- Jonathan M Davis