Undefined reference to _Unwind_Resume and __gxx_personality_v0 - c++

Question

I'm trying to use the JsonCpp library. I'm on Windows, using MinGW and CodeBlocks.
When I include anything from the json headers, my linker implodes and gives out this two errors. I've started to look around and I found these two other questions which basically describe my problem:
problem with g++ and "undefined reference to `__gxx_personality_v0'"
What is __gxx_personality_v0 for?
And if I declare the two missing variables as void pointers, like below, the problem goes away:
void * __gxx_personality_v0=0;
void * _Unwind_Resume =0;
However, I don't understand why this error happens. CodeBlocks is set up so that it uses migw32-g++ for cpp files, and also adding the -lstdc++ option does not fix the problem. Neither does the option -fno-exception ( I want exceptions, mind you, I was just trying ).
I'm also including a boost library in the same file and that does not cause any problems.
EDIT:
The error output is exactly what I said in my title: I get a total of 22 undefined references to _Unwind_Resume and __gxx_personality_v0 during the linking. My code is:
#include <boost/algorithm/string.hpp>
#include <include/json/value.h>
//void * __gxx_personality_v0=0;
//void * _Unwind_Resume =0;
int main () {
std::string str1("Hello world!");
boost::to_upper(str1);
Json::Value k;
return 0;
}
The error is there only when I include/use the JsonCPP library. Uncommenting the commented lines fixes the problem.
The command line output is this:
mingw32-g++.exe -Wall -fexceptions -g -DSFML_DYNAMIC -IC:\Users\Svalorzen\Documents\Projects\boost_1_49 -IC:\Users\Svalorzen\Documents\Projects\jsoncpp-src-0.5.0 -IC:\Users\Svalorzen\Documents\Projects\SFML-1.6\include -IC:\Users\Svalorzen\Documents\Projects\hge181\include -c C:\Users\Svalorzen\Documents\Projects\test\main.cpp -o obj\Debug\main.o
mingw32-g++.exe -LC:\Users\Svalorzen\Documents\Projects\jsoncpp-src-0.5.0 -LC:\Users\Svalorzen\Documents\Projects\SFML-1.6\lib -LC:\Users\Svalorzen\Documents\Projects\hge181\lib -o bin\Debug\test.exe obj\Debug\main.o -fno-exceptions -lsfml-graphics -lsfml-window -lsfml-system C:\Users\Svalorzen\Documents\Projects\jsoncpp-src-0.5.0\libs\mingw\libjson_mingw_libmt.a C:\Users\Svalorzen\Documents\Projects\hge181\lib\gcc\libhge.a C:\Users\Svalorzen\Documents\Projects\hge181\lib\gcc\libhelp.a
Output size is 1.22 MB
Process terminated with status 0 (0 minutes, 3 seconds)
0 errors, 0 warnings
SECOND EDIT:
I'm adding the command lines I use to compile the library:
g++ -o buildscons\mingw\src\lib_json\json_reader.o -c -DWIN32 -DNDEBUG -D_MT -Iinclude src\lib_json\json_reader.cpp
g++ -o buildscons\mingw\src\lib_json\json_value.o -c -DWIN32 -DNDEBUG -D_MT -Iinclude src\lib_json\json_value.cpp
g++ -o buildscons\mingw\src\lib_json\json_writer.o -c -DWIN32 -DNDEBUG -D_MT -Iinclude src\lib_json\json_writer.cpp
ar rc buildscons\mingw\src\lib_json\libjson_mingw_libmt.a buildscons\mingw\src\lib_json\json_reader.o buildscons\mingw\src\lib_json\json_value.o buildscons\mingw\src\lib_json\json_writer.o
ranlib buildscons\mingw\src\lib_json\libjson_mingw_libmt.a

Answer 1

For those coming to this from google (like i did), the real cause of the undefined references to _Unwind_Resume and __gxx_personality_v0 is "using a gcc that uses a different stack unwinding method than dwarf2" [1]
In my case it was attempting to link code compiled with GCC 4.9 upwards with a library compiled with GCC 4.8 or below. The solution is to recompile the library with the same compiler you're building with.

Answer 2

I encountered that same problem attempting to use g++ -g -std=c++17 ... . I removed that option and, once I had removed use of a C++17 feature, it compiled, linked and ran.

Answer 3

I finally fixed this by importing into Code::Blocks the source code of JsonCpp and creating the library myself. I am still baffled though as to why the library created with Scons didn't work, since it was using the same compiler that Code::Blocks uses, but at the same time it was not ( or the error wouldn't have been there ).