On Monday, 6 May 2013 at 02:35:33 UTC, dsimcha wrote:
On the advice of Walter and Andrei, I've written a blog article
about the low-lock Singleton pattern in D. This is a
previously obscure pattern that uses thread-local storage to
make Singletons both thread-safe and efficient and was
independently invented by at least me and Alexander Terekhov,
an IBM researcher. However, D's first-class treatment of
thread-local storage means the time has come to move it out of
obscurity and possibly make it the standard way to do
Singletons.
Article:
http://davesdprogramming.wordpress.com/2013/05/06/low-lock-singletons/
Reddit:
http://www.reddit.com/r/programming/comments/1droaa/lowlock_singletons_in_d_the_singleton_pattern/
FWIW, I played with a generalized form of this pattern long ago,
something like (typing from memory):
template sharedGlobal(alias ctor, alias lock = globalLock)
{
@property sharedGlobal()
{
alias ReturnType!ctor T;
__gshared static Nullable!T t;
static bool instantiated;
if (!instantiated)
{
synchronized(lock)
{
if (t is null)
t = ctor();
}
}
return cast(T)t;
}
alias sharedGlobal!({ return new Blah(); }) blah;
It should have been part of QtD but that has never happened.
