Sharing unlocked, unchanging data between threads?

[Chris Williams]

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.