Sharing unlocked, unchanging data between threads?

[awishformore]

On 10/08/2010 20:01, Steven Schveighoffer wrote:
> On Tue, 10 Aug 2010 13:45:03 -0400, Chris Williams <aahz at seanet.com> 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.
>
> I don't see any reason why you'd need to lock it. It should not be
> modified unless you change/insert a value or remove one.
>
> It's likely something else causing the issue.
>
> -Steve


That and: you should probably declare it as immutable.

/Max