[zeromq-dev] Assertion failed: msg_->flags & ZMQ_MSG_MORE

[Martin Sustrik]

On 04/11/2011 02:25 PM, Berasategui Velasco, Asier wrote:
> Hello.
>
> I'm using ZMQ 2.0.10 version for an communication application.
> Sometimes, without any randomly, this error appears:
>
> "Assertion failed: msg_->flags & ZMQ_MSG_MORE"
>
> I had tried to found some information about this error (to try to
> understand the meaning), but I had only find a piece of information
> related with then in mailing lists archives.
>
> I had read some post about this error, and someone posts that may be,
> this error could be related with "ill-formed" message. ¿Could be?

Yes. That's possible. The other option is that it's a bug that was 
solved in newer versions of 0MQ, but given that you are generating the 
wire format yourself, I would bet on the former to be true.

> In my app I'm want to connect some PCs (linux) with each other and with
> a micro controller, implementing ZMQ headers in Hexadecimal type inside
> the micro controller.
>
> I'm %95 sure that the issue is related with communication between PC and
> micro controller.
>
> Until understand the error, I couldn't fix them, so ¿Someone could
> explain me about this error?

It would help if you've pasted the filename&lineno for the assertion.

Anyway, the assertion complains about not seeing the MORE flag (see 
zmq_tcp(7)) where it is expected to be seen. Presumably, the backtrace 
stack in request/reply pattern is malformed.

Martin