toStringz and toUTFz potentially unsafe

[Johann MacDonagh]

On 7/24/2011 9:06 PM, Jonathan M Davis wrote:
> On Sunday 24 July 2011 17:56:04 Jonathan M Davis wrote:
> The real question is what to do with to!(char*)(str). The plan is to make it
> call toUTFz, but at that point, the warning about toUTFz is not as obvious
> (though it can re-iterate the warning or point you to the toUTFz documentation
> to read it). Also, since you already have toUTFz, calling to!(char*) is kind
> of pointless. So, I think that there's a good argument for forcing to!(char*)
> to append '\0' instead of checking one past the end. Then when you want a
> guarantee that the '\0' isn't going to change, you can use to!(char*), and if
> you want the efficiency, you can call toUTFz. But it is debatable whether we
> should do that or just have to!(char*) call toUTFz in all cases. I'm leaning
> towards making it always copy though.
>
> - Jonathan M Davis

In that case, maybe we should implement @schveiguy's suggestion.

immutable(char)* toStringz(string s, bool unsafe = true) pure nothrow

That way the user can decide whether to take the optimization risk (or 
if they know the string is on the stack, etc...). In addition, always 
copying is wasteful. We're usually able to append a NULL to a dynamic 
array without relocation / copying.