Re: [Discuss-gnuradio] Multiple C files required by single C++ block.How to build?

[Jonas Hodel]

Hello,

Thanks to both Eric and Daniel for your prompt help.

Yes this does make sense and it was the first thing I tried. After it didn't work with my files I went right back to basics (I am building a la gr-howto-write-a-block). I created very simple .h/.c files as a test.

------------------------------------------------------------------------------------
/*test.h*/

#ifndef __TEST__
#define __TEST__

void jonas_test();

#endif

------------------------------------------------------------------------------------
/*test.c*/

#include "test.h"
#include <stdio.h>

void jonas_test()
{
    printf("this is a test, proof is in the pudding\n");
}

------------------------------------------------------------------------------------

Then:
Within “howto_square2_ff.h” I added #include “test.h”.
Within  “howto_square2_ff.cc” I added a call to jonas_test(), located in the constructor howto_square2_ff ().
I added test.c to the “_howto_la_SOURCES” entry in “src/lib/Makefile.am”.

Finally: “make clean”, “make” and “make check”.

This results in:

ImportError: /home/jonas/gnuradio/gr-howto-write-a-block-3.0.2/src/lib/.libs/_howto.so: undefined symbol: _Z10jonas_testv

I tired other variations (creating test.i, included in howto.i etc) but I must be missing something fundamental.

Thanks again for you help!

Eric Blossom wrote:

On Wed, Nov 29, 2006 at 10:39:20AM +1030, Daniel O'Connor wrote:
  

On Wednesday 29 November 2006 09:26, Jonas Hodel wrote:
    

I have some existing C-functions which I would like to include in a C+
signal processing block. The complication is that these C-functions are
located in a number of different files. I have created a C++ block which
uses these functions. It appears to build fine but when I come to
include the new block in my python script I get an “undefined symbol”
error referring to one of the low level C-functions (I think). In short,
is it possible to use my existing C-files unchanged (included in my C++
block)? If so what approach is necessary to make this work/build properly?
      

You need to compile those .c files into .o files and then link all your .o 
files together then it should work fine.

I don't know how to get the GNURadio build system to do that for you though 
(probably just appending the names of the .c files to the list of source 
files will do it though)

    

This is correct.  You just need to arrange so that those files end up
in the same shared library as the block that's using them.

Just add the the .c files to the <foo>_la_SOURCES entry in the
appropriate Makefile.am

Are you building this outside of the main tree a la
gr-howto-write-a-block, or in the main tree?  The idea is the same in
both cases.

Does this make sense?

Eric
  

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