Re: SSO

Jerry Coffin wrote:


  Could you please elaborate more on *why*? I just can't see that happening.

  Let's assume we have two threads running, A and B. Thread A owns a
string which it wants to pass to thread B. How does it do that?

  I assume that thread A sees some string that is owned by B, and then
goes and assigns it to that string. Let's assume the string uses a
deep-copy.

  If *during* that deep-copying thread B starts reading the string, it
will get incorrect data (because it has only been partially copied).

  The other possibility I can think of is that thread B makes the copy.
In other words, it sees the string owned by thread A, and assigns it to
its own string.

  Again: If thread A goes and modifies its string while this
deep-copying is happening, the data which is copied to B will become
corrupted.

  I just can't see how deep-copying solves any synchronization problems.
The only way to copy the string from A to B safely is to lock access to
it for the duration of the copying (regardless of how the copying is
done). I can't see any other way.