Aaaah, it's the dreaded max_samps_per_buffer:( Yup, you need to make your read buffer aligned to max_samps_per_buffer...
HTH Nikos On Sun, Aug 14, 2022 at 9:24 PM <wozn...@gmail.com> wrote: > > Nikos, > > Thanks for the reply. I traced it to the “recv” call which has left me > puzzled. I added a bunch of instrumentation to see if I was walking off the > end of my memory that was allocated to the 16-bit I/Q buffer. > > const std::int32_t startIndex = 2*num_accum_samps; > > const std::int32_t remainingSize = 2*sampleLength-(2*num_accum_samps); > > std::cout << "iq[" << startIndex << "] = " << iq[startIndex]; > > std::cout << "\t" << remainingSize; > > std::cout << "\t" << startIndex + remainingSize; > > std::cout << "\t" << bufferSize << std::endl; > > num_accum_samps += rx_stream->recv(&iq[startIndex], remainingSize, meta, 5.0, > true); > > And I can get it to faithfully crash every single time when I don’t pad my > array of 16-bit integers by an additional 2165 int16s. I included some output > indicating where I’ve specified as the start of the buffer for it to write > to, followed by the remaining size, followed by the sum of the two just to > make sure I can math, and finally the actual reserved buffer size plus the > pad of 2164 int16s. > > … > > iq[1180480] = 0 19520 1200000 1202164 > > iq[1185920] = 0 14080 1200000 1202164 > > iq[1191360] = 0 8640 1200000 1202164 > > iq[1196800] = 0 3200 1200000 1202164 > > Segmentation fault (core dumped) > > If you’ll notice, I’ve specified for it to start at index 1196800 and that > the number of samples per buffer being passed to recv() is 3200. I think I’m > just being dense / misinterpreting the nsamps_per_buff (the second parameter > of the “recv” call) because it seems as if it is not respecting the remaining > buffer size that I am specifying and attempting to write beyond the bounds of > the memory I’ve allocated for the buffer. > > Is there some alignment or minimum buffer size that I’m not aware of? > > Thanks, > > Chris > > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com _______________________________________________ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
