Does the message port propagate tags?

GNU Radio
1

Hi all,

I’ve been wondering if a message port propagate the tag that come from a
previous input ports. I’ve been reading about propagation and
propagation
politics and I was just playing around putting a Tag debug in front of
several blocks connected to a USRP source that is generating a rx_time
tag.

However, staying with the default “all to all” politic, at some point I
was
just wondering about the message port, as it doesn’t really count as an
in/output port at the signatures, and also the “Tag debug” port has no
“message” option for the input (maybe for obvious reasons that answer my
question) However I would just like to have it clear.

Thank you all in advance.

Regards

luikn

2

Hi Luikn,

Message ports and stream tags are orthogonal concepts: messages don’t
come in streams, and hence don’t carry stream tags.
A tag is always specific to a numbered item, and since message ports are
not item-based but meant to transport messages that will cause a handler
to be called in the receiving block’s thread, there’s nothing to
“attach” a stream tag to.

Best regards,
Marcus