[Discuss-gnuradio] GRC problems

[Johannes Demel]

Hi list,

I discovered 2 problems with GRC recently.

1. I have a custom block with a message port (with a fixed port name)
and some stream ports which include a <nports>...</nports> definition.
The whole thing works fine as long as I have a fixed number of ports.
Each declared separately. But as soon as I use a nport statement GRC
won't display this block correctly [1]. Even worse if I enter values
which affect the number of ports, the whole flowgraph will disappear.
Just a grey flowgraph page.

2. To make things easier for me (and to not create a well known kind of
artwork) I use hier blocks. This works fine as long as I have fixed size
vector ports. But adding a parameter block, say vlen, for vector size to
dynamically change the hier block doesn't work. The python generator
does not generate the hier block python file with vlen as vector size.
Instead it puts in the default value. A parameter block without default
value results in an error. A hard coded vector size is not exactly
helpful in this case.

I didn't have time to dig into it yet. Thus I thought I share my
experience with you. Maybe I am not the only one with this problem and
someone already knows how to fix it.

Happy hacking
Johannes

[1]
<sink>
  <name>msg</name>
  <type>message</type>
  <optional>1</optional>
</sink>

<sink>
  <name>in</name>
  <type>complex</type>
  <vlen>$vlen</vlen>
  <nports>$ports</nports>
</sink>