Proper way to protect (lock) a struct field after initialization ??

[james.p.leblanc via Digitalmars-d-learn]

Hello All.

Is there a standard way to protect a field of a struct after
the struct has been initialized?

Is this possible with a struct?

If not, I suppose a class (object) would be needed?  If so,
are there any simple pointers to an example of this?

Thanks in advance,

James