On 2010-08-10 20:40, Jonathan M Davis wrote:
On Tuesday, August 10, 2010 10:45:03 Chris Williams wrote:
I'm writing a fairly large, multithreaded application and some part
of it is causing periodic access errors.
Say that I have an associative array like:
uint[ char[] ] nameToId;
If I set all values before I start my threads going and never change
anything after that point -- all access is read only -- is there any
way that having multiple threads access it at the same time would
mess anything up? I'm doing this in several places as locking a
read-only data structure doesn't strike me as something which should
be necessary. I don't know what D's associative arrays look like
internally though, so perhaps it is dangerous to do. It would be a
major hassle to port it all over to locking everything, to test if
it fixes the problem. So, hopefully someone can say whether this is
worth checking.
Well, unless it's declared shared, it's going to be thread-local, and then each
thread is going to have their own copy. Now, if it were declared shared and you
never changed it after initially setting all of its values, then you shouldn't
have any problems as far as I'm aware. Just accessing an associative array
shouldn't change it.
- Jonathan M Davis
I though immutable was supposed to be implicitly shared with no need for
locks or read-write barriers (or what they're called).
--
/Jacob Carlborg
