[Discuss-gnuradio] arbitrary or variable numbers of inputs or outputs

[Johnathan Corgan]

Forgot to copy the list.

---------- Forwarded message ----------
From: Johnathan Corgan <address@hidden>
Date: Wed, Apr 1, 2009 at 9:17 AM
Subject: Re: [Discuss-gnuradio] arbitrary or variable numbers of
inputs or outputs
To: Dimitris Symeonidis <address@hidden>


On Wed, Apr 1, 2009 at 8:57 AM, Dimitris Symeonidis <address@hidden> wrote:

> Lately I've been getting a strange error message when running a python
> graph that contains the wfm_rcv_pll block:
>
> Exception RuntimeError: 'maximum recursion depth exceeded while
> calling a Python object' in <type 'exceptions.AttributeError'> ignored

The above is a known bug triggered when using Python 2.6.

>    gr.io_signature(1, 2, gr.sizeof_float))      # Output signature

> RuntimeError: Hierarchical blocks do not yet support arbitrary or
> variable numbers of inputs or outputs (wfm_rcv_pll)

This is a new warning message recently added to indicate the requested
io signature for a hierarchical block is unsupported (but will be in
the future at some point.)  Hierarchical blocks currently only support
a fixed number of inputs or outputs; the above signature is declaring
that it is possible to have either 1 or 2 outputs connected to the
block.

It turns out the blks2.wfm_rcv_pll hierarchical block was declaring
this to support either mono or stereo output, but really only had
stereo outputs.  Everything worked okay, but now the stricter checking
on signatures catches the mistaken io signature declaration. I'm going
to changed the signature to 2, 2 and this message will go away.

We do plan to support variable io signatures in hierarchical blocks
(hence the 'yet' in the error message).

Johnathan