What exactly does "@safe" mean?

[Steven Schveighoffer]

On Sun, 02 Jun 2013 03:59:08 -0400, monarch_dodra <monarchdodra at gmail.com>  
wrote:

> On Saturday, 1 June 2013 at 22:15:00 UTC, Jonathan M Davis wrote:

>> Well, given that the safety of the operation relies on what's being  
>> passed in,
>> the operation itself can't reasonably be marked as @safe, because you  
>> can't
>> guarantee that the operation isn't going to corrupt memory.
>
> But isn't that exactly the same as my "void foo(int* p) @safe{*p = 0}"  
> example ? That relies on what is being passed in to guarantee safety :/
>
> @confused

provable @safe depends on the precondition that its parameters are valid  
and @safe.

The easiest way to do this is to mark main as @safe.  Then you can't go  
unsafe.

As people have pointed out, there are bugs/holes.  They need to be fixed.

@trusted should be used VERY cautiously.  It basically says "I know this  
is @safe, but the compiler can't prove it".  These situations should be  
very very rare.

Think of @safe functions as bricks.  By themselves, they are solid and  
will hold up a building well.  But if you put them on top of garbage, they  
will be as useless as cardboard.

-Steve