Undefined Reference when compiling ThorSerializer example - c++

Question

I am looking into JSON Serializer/ Deserializer c++ libraries and found the ThorSerializer to have all essential functoinalities and it keeps the variable names of key value pairs in the JSON Format as they are when serializing user defined classes, without replacing the keys with generic names, which is exactly what I need.
When I try to compile the basic example provided on the project's home page:
#include "ThorSerialize/Traits.h"
#include "ThorSerialize/JsonThor.h"
struct Shirt
{
int red;
int green;
int blue;
};
class TeamMember
{
std::string name;
int score;
int damage;
Shirt team;
public:
TeamMember(std::string const& name, int score, int damage, Shirt const& team)
: name(name)
, score(score)
, damage(damage)
, team(team)
{}
// Define the trait as a friend to get accesses to private
// Members.
friend class ThorsAnvil::Serialize::Traits<TeamMember>;
};
// Declare the traits.
// Specifying what members need to be serialized.
ThorsAnvil_MakeTrait(Shirt, red, green, blue);
ThorsAnvil_MakeTrait(TeamMember, name, score, damage, team);
int main()
{
using ThorsAnvil::Serialize::jsonExporter;
TeamMember mark("mark", 10, 5, Shirt{255,0,0});
// Use the export function to serialize
std::cout << jsonExporter(mark) << "\n";
}
I always end up receiving the following error output
/usr/bin/ld: CMakeFiles/test.dir/src/test.cpp.o: in function `main':
test.cpp:(.text+0xb7): undefined reference to `ThorsAnvil::Serialize::defaultPolymorphicMarker[abi:cxx11]'
/usr/bin/ld: CMakeFiles/test.dir/src/test.cpp.o: in function `ThorsAnvil::Serialize::JsonPrinter::~JsonPrinter()':
test.cpp:(.text._ZN10ThorsAnvil9Serialize11JsonPrinterD2Ev[_ZN10ThorsAnvil9Serialize11JsonPrinterD5Ev]+0x13): undefined reference to `vtable for ThorsAnvil::Serialize::JsonPrinter'
/usr/bin/ld: CMakeFiles/test.dir/src/test.cpp.o: in function `ThorsAnvil::Serialize::operator<<(std::ostream&, ThorsAnvil::Serialize::Exporter<ThorsAnvil::Serialize::Json, TeamMember> const&)':
test.cpp:(.text._ZN10ThorsAnvil9SerializelsERSoRKNS0_8ExporterINS0_4JsonE10TeamMemberEE[_ZN10ThorsAnvil9SerializelsERSoRKNS0_8ExporterINS0_4JsonE10TeamMemberEE]+0x65): undefined reference to `ThorsAnvil::Serialize::JsonPrinter::JsonPrinter(std::ostream&, ThorsAnvil::Serialize::PrinterInterface::PrinterConfig)'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/test.dir/build.make:103: test] Error 1
make[1]: *** [CMakeFiles/Makefile2:95: CMakeFiles/test.dir/all] Error 2
make: *** [Makefile:103: all] Error 2
I am using the header only version and my CMakeLists.txt looks as follows:
cmake_minimum_required(VERSION 3.4 FATAL_ERROR)
project("test")
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
find_package(Pistache REQUIRED)
include_directories(include)
add_executable(test src/test.cpp)
target_include_directories(test PUBLIC include include/ThorsSerializer)
To me it looks like the compiler can't find certain functions, although all of them are present in the respective header files and the namespaces. I checked for typos and similar but can't find the cause for my problems.
Does Anyone know what I might be doing wrong?

Answer 1

At the very beginning, you have to define a macro HEADER_ONLY by including a special header file named "ThorSerialize/SerializeConfig.h". This will unlock template definition functions located in .tpp file and remove "undefined definition" at compilation time.
Although, you may encounter other troubles because of "#endif" declared without its corresponding "#if". The quick fix I found, is to comment last line "#endif" of these following files:
ThorSerialize/CustomSerialization.source
ThorSerialize/Serialize.source
And finally, it will compile.