On 05/09/2019 02:54 PM, Albin Stigö wrote:
Every instance of a block is an instance of the c++ class but like
Nick says all your variables are static and not member variables.
Those need to be declared in the header. Your two block instances are
referring to the same variables and that's why things get messed up.
"A tour of C++" by Bjarne Stroustrup is a good refresher on C++.
--Albin
I'm going to suggest, ever-so-gently, that discuss-gnuradio, and Gnu
Radio in general aren't the places for learning C++. There are forums
already for that.
I'm saying this only because in the 15 years (!!!!) I've been involved
with Gnu Radio, I see an alarming number of cases where the
intrepid Gnu Radio developer actually doesn't have much in the way of
programming experience in the underlying languages used,
and arrives here, nearly-certain that their problem is GR related,
rather than an improper use of the underlying programming language.
My guess is that other specialized-framework environments have the same
issue. Fortunately, most people here are helpful regardless.
But it shouldn't be a growing *expectation*, IMHO.
On Thu, May 9, 2019, 20:46 Nick Foster <bistrom...@gmail.com
<mailto:bistrom...@gmail.com>> wrote:
It looks like you've declared a bunch of static variables within
your block's namespace. Those variables (including pointers!) will
be shared with every instance of your block. This is Bad News.
Those variables should probably all be declared in the header as
class member variables.
On Thu, May 9, 2019 at 11:43 AM Brad Hein <linuxb...@gmail.com
<mailto:linuxb...@gmail.com>> wrote:
I'm running into a strange issue with a new flow graph [1] I'm
working on that uses a custom C++ block [2] that I built. The
block takes input samples, performs some DSP, and outputs
modified samples at the same sample rate.
When the flowgraph has a single instance of my custom block
enabled, it works fine. But when I enable a second instance of
the block in a separate second usage, (think stereo sound, one
per sink channel) it acts very unexpectedly - output samples
are wildly inaccurate and distorted.
My perception is that the two instances of the same block seem
to be sharing some part of their memory namespace and as they
modify/store variables they are doing so in some sort of
shared namespace or memory segment.
Is it possible for two blocks to corrupt each other's memory?
I can't think of any other explanation for the two streams
working fine individually, but when both are enabled at the
same time the output is garbled. I've tried all sorts of
things like tying them to the same source block, removing the
upsampling/downsampling, adding a delay to one, etc. with no
luck.
[1] "Flowgraph with two parallel streams both using the custom
block pq_rails":
https://github.com/regulatre/gr-powerquality/blob/master/examples/streamer.grc
[2] "pq_rails (Custom block) source code":
https://github.com/regulatre/gr-powerquality/blob/master/lib/pq_rails_impl.cc
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