Problems using multiple C files in OOT Block

[George Edwards]

Hello GNURadio Community,

With complex algorithms, there are times when one needs to add C files to
an OOT module on top of those created by the gr_modtool to make the coding
more modular and cleaner. I made a try with a trivial C++ adder
function file, but
could not get it to work. Below is a description of what I did:

I created an OOT C++ module name tutorial and added the block my_adder_ff with
inputs float a and float b.

gr_modtool creates the files my_adder_ff_imp.cc and my_adder_ff_imp.h

In the module lib directory, I created an additional C++ file named
my_add_function.cc containing the definition for the function my_add(float
a, float b). Inside this file I included the header:
#include "my_adder_ff_imp.h"
And, wrapped the function definition in the namespaces:
namespace gr {
    namespace tutorial{
           float my_add(float a, float b){
                   float c;
                   c = a+b:
                    return c
           }
    }
}

I further did the following:
1. Inside my_adder_ff_imp.h , I declared  float my_add(float a, float b)
 2. I called the adder,  val = my_add(a, b) inside my_adder_ff_imp.cc
 3. In the CMakeLists.txt in the lib directory, I included the source file
my_add_function.cc under my_adder_ff_imp.cc (already included by the
gr_modtool)
When I compiled and run, it failed because it could not see the function
my_add.

Will appreciate any help in leading me towards resolving this issue.

Regards,
George