[Discuss-gnuradio] Detecting "EOF" in stream-in-message-out block

[Peter Horvath]

Hi,

I'm having hard time using GNU Radio to replace Simulink :)

I'd like to build a QA flowgraph (think of evaluating a BER vs. SNR 
curve) to assess the performance of my signal processing chain. The 
problem is that the signal processing chain starts with blocks passing 
messages around, then there are ordinary stream blocks, but at the 
receiving side, I again have a block with stream input and message output.

Propagating PMT_EOF tags on the transmitter side takes care of shutting 
down the flowgraph whenever I want it to, and as the input for the 
stream blocks dry up, they die nicely as well. However, I'm unable to 
detect the end of the "input" in my receiver block, which takes stream 
and produces message. The flowgraph simply hangs indefinitely as 
expected (?), because I don't propagate EOF PMTs downstream, and hence 
set_done() doesn't get called down the path.

I'd like to avoid passing stream tags through the stream blocks from the 
transmitter to the receiver, for multiple reasons (not only because I'm 
lazy but it'd also require changing a lot of stuff in the intermediate 
message-passing blocks. Also EOF should be able to come after the last 
piece of data, independently, not somehow glued to it.)

Is there a better way to detect this?
Thanks,
Peter