Pointers vs. References

[Dan]

Lionello Lunesu Wrote:

> Michael Neumann wrote:
> > Synapse x = ...;
> > while (x != null)
> > {
> > }
> > 
> > This segfaults, while:
> > 
> > Synapse x = ...
> > while (!(x is null))
> > {
> > }
> > 
> > does not.
> 
> That's not a bug.
> '==' and '!=' result in a call to opEquals, which is likely to segfault 
> when one of the operands is null. You should use 'is' or in your case '!is'.
> 
> while (x !is null)
> {
> }
> 
> As for your question about references. A reference is basically the same 
> as a pointer, so there should be no performance difference between the 
> two. Without more details, it's hard to say what could be the reason 
> behind the bad performance.
> 
> L.

Heh... using classes in any language will cut your performance compared to using structs.  D has nice structs.  References are pointers to pointers to something; not "the same".  Also, using while(x !is null) after explicitly defining it is usually wrong; you usually want do { ... } while(x !is null);  That's all I can gather though from your vague post.