Re: [Discuss-gnuradio] Using Out-of-Tree module from C++ Application

[Tom Rondeau]

On Mon, May 13, 2013 at 8:00 PM, Michael Buettner
<address@hidden> wrote:
> I am trying to use an out of tree module (built according to the
> "Out-of-tree modules" documentation) from a C++ application. The
> module is named "reader", and the block I'm trying to use is
> "command_gate_cc".
>
> I can use it from python with:
>   from reader import reader_swig
>   ...
>   cg_block = reader_swig.command_gate_cc_make()
>
> I can't figure out how to create a command_gate_cc block in C++ though.
>
> /usr/local/lib/libgnuradio-reader.so exists, and 'nm -CD
> /usr/local/lib/libgnuradio-reader.so' gives me
> '0000000000004850 T gr::reader::command_gate_cc::make()'
>
> /usr/include/reader_command_gate_cc.h exists:
>
> namespace gr {
>   namespace reader {
>
>     class READER_API command_gate_cc : virtual public gr_block
>     {
>      public:
>       typedef boost::shared_ptr<command_gate_cc> sptr;
>       static sptr make();
>     };
>
>   } // namespace reader
> } // namespace gr
>
> My CC applications has:
> #include <command_gate_cc.h>
> ...
> boost::shared_ptr<gr::reader::command_gate_cc> cg =
> gr::reader::command_gate_cc::make();

I think you're pretty close.

First, you can use the sptr from the class itself:
gr::reader::command_gate_cc::sptr = gr::reader::command_gate_cc::make();

> But I get the linker error:
> undefined reference to `gr::reader::command_gate_cc::make()'
>
> What am I missing? I don't understand the build system well enough to
> figure out where if that is where I'm going wrong. Any help would be
> appreciated. Thanks!

Looks like you aren't linking properly to your libgnuradio-reader.so.
Take a look at gr-audio/examples/c++/CMakeLists.txt for how you can
set up a cmake file properly.

Tom