Re: [Discuss-gnuradio] Compilation Error of the sample code "tags_demo.cc"

Hi,

I created an OOT module, added the UHD into the required components and added the following lines in the top-level CMakelist.txt and the CMakelist.txt under the apps folder.

The tesr.cc just makes a top_block:  gr::top_block_sptr tb = gr::make_top_block("tags"),

which leads to undefined reference.

If I add another line "gr::uhd::usrp_source::sptr usrp_source = gr::uhd::usrp_source::make(device_addr, uhd::stream_args_t("fc32")); ", the error is:

I think it is a linker problem, but I can not find what I am missing. Is there anyone who could help me fix this?

Thanks,

Zhihong

On Thu, Feb 4, 2016 at 9:34 AM, Zhihong Luo <zhluo@umich.edu> wrote:

Hi Tom,

Thank you for the advice. The website seems to be really useful.

Zhihong

2016年2月4日星期四，Tom Rondeau <tom@trondeau.com> 写道：

On Wed, Feb 3, 2016 at 8:28 PM, Zhihong Luo <zhluo@umich.edu> wrote:

Hi Marcus,

Can you be more specific about what I need to add to the CMakeLists.txt? Because in the <modulename>/apps/CMakeLists.tx, there is no "sources", but only:

include(GrPython)

GR_PYTHON_INSTALL(
    PROGRAMS
    DESTINATION bin
)

And in the <modulename>/CMakeLists.txt, what do you mean by "Add "uhd" to the list"? Is it "find_package(UHD)"? Or things like including ${UHD_INCLUDE_DIRS} ${GR_UHD_INCLUDE_DIRS}

to the directory? I try to learn from the built-in gr-uhd, but there is no apps folder and its CMakeList.txt looks very different. So I was lost.

I am really unfamiliar with these, so more detailed explanation will be much appreciated. Thanks.

Zhihong Luo

We appreciate your enthusiasm for use GNU Radio and building stuff with it. However, the questions you are asking are more related to C++, makefiles, and CMake. I think you'd be better off studying those and learning the basics before asking questions like that here.

Another tactic you can take is to look at all of the projects available on cgran.org as well as look at the GNU Radio source code itself. We have lots of examples out there that you can learn from to do what you want here.

Tom

 

On Wed, Feb 3, 2016 at 3:56 AM, Zhihong Luo <zhluo@umich.edu> wrote:

Hi Marcus,

Thank you for the detailed instructions! I'll test it tomorrow and hopefully it can work :) Have a good night.

Zhihong 

2016年2月3日星期三，Marcus Müller <marcus.mueller@ettus.com> 写道：

Hi Zhihong Luo,

you're not linking your program against any GNU Radio component, which is why the linker step in your compiler call complains about all the symbols from these libraries missing.
Normally, it's the job of a build system to set up your compiler call correctly, but in this case, somethin like

g++ tags.cpp -o tags $(pkg-config --libs --cflags gnuradio-runtime gnuradio-uhd)

should work.

I'd still recommend not doing that, but using gr_modtool to create a new out-of-tree module

gr_modtool newmod

and add your file in the <modulename>/apps/ folder, adding the filename to <modulename>/apps/CMakeLists.txt under "sources". Add "uhd" to the list of necessary GNU Radio components in <modulename>/CMakeLists.txt

Then, it's the normal CMake build procedure:

cd <modulename>
mkdir build
cd build
cmake ..
make
make install

On 03.02.2016 09:39, Zhihong Luo wrote:

Hi Marcus,

Sorry, I was typing and accidentally sent it out the previous one... The code is 

#include<gnuradio/top_block.h>

#include<gnuradio/uhd/usrp_source.h>

#include<uhd/utils/safe_main.hpp>

#include <boost/make_shared.hpp>

#include <boost/thread/thread.hpp>

#include <boost/program_options.hpp>

#include <csignal>

#include <iostream>

namespace po = boost::program_options; int UHD_SAFE_MAIN(int argc, char *argv[]){ std::string device_addr =" "; gr::top_block_sptr tb = gr::make_top_block("tags_demo"); gr::uhd::usrp_source::sptr usrp_source = gr::uhd::usrp_source::make(device_addr, uhd::stream_args_t("fc32"));

}

Then I ran the command:

g++ tags.cpp -o tags -l boost_system

which ends up having errors:

undefined reference to gr::make_top_block, uhd::device_addr_t, gr::uhd::usrp_source and etc.

Thanks,

Zhihong Luo

On Wed, Feb 3, 2016 at 4:29 PM, Zhihong Luo <zhluo@umich.edu> wrote:

Hi Marcus,

Of course. Here are the codes:

On Wed, Feb 3, 2016 at 4:13 PM, Marcus Müller <marcus.mueller@ettus.com> wrote:

Hi Zhihong Luo,

could you please rather share text than pictures of text, too small for reading?

Best regards,
Marcus

On 03.02.2016 07:31, Zhihong Luo wrote:

Hi all,

I just started to learn to use c++ for gnuradio, and I copied some codes from the "tags_demo.cc". But compilation error occurred as shown in the following screen shots. Can you tell me where I made a mistake?

Thanks,

Zhihong Luo

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