Re: Hazard pointers needed with GC ?

[Timon Gehr]

On 12/07/2011 06:02 PM, Martin Nowak wrote:
I implemented a lock-free doubly linked list some time ago.
I omitted the use of hazard lists because flagging the lowest
bit would still make a valid pointer into the list node.
Afterwards I found that
http://www.d-programming-language.org/garbage.html explicitly states:
p = cast(void*)(cast(int)p | 1); // error: undefined behavior
Is this really needed? Guess the current GC would work properly.

Also if a list node were
Node(T)
{
ubyte[2] data;
T t;
}
Than both a pointer to data[0] as well as one to data[1] are valid
and effectively hold the node.

martin

TDPL suggests that using that kind of pointer flagging is sane. Maybe 
you can file a bug against the specification.