immutable string literal?

[Steven Schveighoffer]

On Mon, 22 Feb 2010 10:19:52 -0500, grauzone <none at example.net> wrote:

> Steven Schveighoffer wrote:
>> On Mon, 22 Feb 2010 09:27:57 -0500, strtr <strtr at spam.com> wrote:
>>> Thanks, I understand.
>>> But, how about a runtime error?
>>> Isn't a literal placed in easy to identify should-only-read memory?
>>  A segfault is a runtime error.  The problem with Windows is it doesn't  
>> throw an error on writes to its data segment (unlike Linux).  In  
>> reality, the result of your program is undefined, so don't expect any  
>> help from the compiler/runtime.  There's nothing D1 can do about that.   
>> In order for D to intercept that, it would have to instrument every  
>> write to memory, and that would cause performance problems like you  
>> wouldn't believe.
>
> Windows can protect memory as read-only too. Why dmd doesn't do that is  
> a mystery. Even if .exe doesn't support read-only data segments, the  
> runtime could have done so in early start-up code.

I'm not super-familiar with windows capabilities, but I'd venture a guess  
that doing so would make exe's not compatible with older versions of  
Windows.

But still, what does it matter?  Just don't use D1 if you want a compiler  
error, or don't try and trick the system into modifying ROM!  There are  
plenty of projects using D1 that just don't do this, and they are fine.   
Implementing features to help people determine they created undefined  
behavior is simply a waste of time.  If you feel you can fix it, by all  
means submit a patch, and it might get in.

-Steve