[zeromq-dev] Maybe a ZMQ_LOST socket

[Pieter Hintjens]

On Wed, Jun 29, 2011 at 4:21 PM, Martin Sustrik <sustrik at 250bpm.com> wrote:

> This is called "dead letter queue" in MQ-speak.
> However, it probably doesn't have the semantics you expect it to have.
>
> It's not a queue of lost messages, rather it's a queue of messages with
> unclear status. They may have been lost, but they may have been
> delivered (only the delivery acknowledgement was lost).

In any case, ROUTER will queue and hold messages to peers that have
gone offline, and the only way to dead-letter these would be with a
timeout on connection (at which stage any undelivered messages could
be dead-lettered).

As for invalid addresses, since this is an application error by
definition, I'd argue it's worth making this assert. (Especially if we
kill explicit identities and thus any scenario where ROUTER discarding
a message makes sense).

-Pieter