In this case, there is an extra bit of confusion because an empty PMT
dictionary `pmt.make_dict()` is represented by (and the same as) `pmt.PMT_NIL`.
An interned string, as in your first example, is not a dictionary type object
and thus you get the warning message.
Jacob
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, November 19th, 2021 at 3:30 AM, Vasil Velichkov
<vvvelich...@gmail.com> wrote:
> Hi Marcin,
>
> On 18/11/2021 15.23, Marcin Puchlik wrote:
>
> > *pmt.cons(pmt.intern(""), pmt.make_u8vector(16, 0xFF)) - *where Debug
> >
> > block cannot extract the PDU - gr::log :WARN: message_debug0 - Non PDU type
> >
> > message received. Dropping.
>
> Not every message is a PDU [1]. Have a look at is_pdu() in pmt.h [2] and read
> the discussion in issue #4191 [3].
>
> /*!
>
> - Returns true if the object is a PDU meaning:
> - the object is a pair
> - the car is a dictionary type object (including an empty dict)
> - the cdr is a uniform vector of any type
>
> */
>
> PMT_API bool is_pdu(const pmt_t& obj);
>
> [1] https://wiki.gnuradio.org/index.php/Message_Passing#PDUs
>
> [2]
> https://github.com/gnuradio/gnuradio/blob/maint-3.9/gnuradio-runtime/include/pmt/pmt.h#L707-L713
>
> [3] https://github.com/gnuradio/gnuradio/issues/4191
