Does ZODB provide safe locking across mutiple-processes?

[June Kim]

I'm considering using ZODB on Win32 and *nices.

The FileStorage seems to have some sort of file locking for both the
platforms.

I wonder if it guarantees "many readers or one writer" style
exclusive/shared locking -- that is, is it safe to open the same DB in
read_only mode and to open it in writable mode again, as ZODB allows?

Thanks in advance.