Re: [Discuss-gnuradio] Output block: vector of a vector

Hi Alice - Inside "work" or "general_work", all you have is access to is pointers to buffers. The "shape" of them is inferred by the block implementation specifics, for example a pointer to unsigned char array, or pointer to float array. Recasting pointers as you describe will cause a crash, because the std::vector structure isn't valid. You can, on the other hand, instantiate a std::vector in the ::work code & provide it with the memory location of the data & length & that could work. Does this make sense? If not, maybe read up on the inner working of GR via some of TomR's presentations from GRCon & elsewhere; poke through the code in gnuradio-runtime to get an idea of the GR workings behind the scenes; read up on how C++ classes & memory allocations work. Doing those sorts of things will increase your knowledge base & improve how you use GR and interact with this list. Hope this helps! - MLD

On Wed, Nov 29, 2017, at 11:30 AM, Alice Lo Valvo wrote:

I'm wondering if it is possible to make an output of a block that is a vector of a vector.

I tried with:

    int

    vector_source_tagged_impl::work(int noutput_items,

        gr_vector_const_void_star &input_items,

        gr_vector_void_star &output_items)

    {

      std::vector<int> *optr = (std::vector<int> *) output_items[0];

and there are not compiling errors, but when I run GRC, it stops with this:

Executing: /usr/bin/python -u /home/alice/project_GNURADIO/tx_ofdm.py

Using Volk machine: avx2_64_mmx_orc

>>> Done

Any suggestions?

Thanks in advance.