core.runtime.GC memory alignment

[David Nadlinger]

On Sunday, 27 October 2013 at 16:19:28 UTC, Peter Alexander wrote:
> "The malloc() and calloc() functions return a pointer to the 
> allocated memory that is suitably aligned for any kind of 
> variable."
>
> I see no reason to diverge from that.

Welö, except for the fact that "any kind of variable" is not 
well-defined for a language that supports user-defined alignment 
restrictions:

---
struct Foo {
     align(8192) byte b;
}

template Seq(T...) { alias Seq = T; }
void main() {
     import core.memory, core.stdc.stdio, core.stdc.stdlib;
     foreach (alloc; Seq!(malloc, GC.malloc)) {
         auto mem = cast(Foo*)alloc(Foo.sizeof);
         printf("%u\n", cast(uint)(cast(size_t)mem & (Foo.alignof 
- 1)));
     }
}

---

David