[zeromq-dev] Assert in XSUB (send_subscription)

[Pieter Hintjens]

On Mon, Dec 19, 2011 at 9:01 AM, Daniel Lundin <dln at eintr.org> wrote:

> send_subscription will assert if the socket has reached SNDHWM, where
> it before would eventually run out of memory if a corresponding PUB
> peer never showed up.
>
> In any case, an assertion is pretty harsh when reaching exceptional state.

Silently consuming infinite memory is nasty; the assertion is a
placeholder for "please insert better strategy here". In this case,
harsh is what we want.

> I don't have a good idea what behavior an XSUB *should* exhibit in
> that case, though, I think perhaps it'd make more sense to block (like
> PUSH)?

Blocking seems the right strategy since it's consistent with other
reliable outgoing sockets. Returning an error just means every
application has to handle this (and most won't handle it properly).
Setting HWM to infinite is the worst strategy IMO.

-Pieter