Marcus Brinkmann <[EMAIL PROTECTED]> writes: > On Wed, Jan 30, 2002 at 02:52:30PM -0800, Thomas Bushnell, BSG wrote: > > The Right Thing is surely two separate threads. I'm not sure that > > select is really necessary at all however. > > I have stumbled upon an obscure race where it helps. I am not sure if > it is worth the use of io_select, I will leave this for you to decide.
A race should always be avoided if it makes a bug. But there may be a way to avoid it without select. > The issue I am talking about is implementing pending_output_size correctly, > which should return the number of bytes pending for output. The problem > exists only for ioports that have the tiocoutq capability. Because we don't > know if the underlying translator already has received the io_write or not, > we don't know what the correct return value is: pending_output_size is always approximate. Users cannot rely on it being totally synchronized. The situation you describe here occurs for almost all serial hardware in existence, and it's not a reason to worry about anything else. So this case is a sort of race, but it's not a bug, because we don't actually need to worry about the exact value. > Now, after the signature, an excerpt from the current implementation of the > writer loop. What do you think? Looks reasonable to me. I assume that this function is the only one that mucks with the pending_output array? _______________________________________________ Bug-hurd mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/bug-hurd
