Undefined Reference when Compiling Kobuki ROS examples from source - c++

Question

I have been trying to compile the kobuki_keyop example in ROS Indigo from source on Ubuntu 14.04, I basically wrote a simple cpp file like the following:
#include "/opt/ros/indigo/include/kobuki_keyop/include/keyop_core/keyop_core.hpp"
using namespace keyop_core;
int main()
{
KeyOpCore keyy;
}
then I compiled with the following:
g++ test.cpp -L/opt/ros/indigo/lib/kobuki_keyop -o test
but it keeps giving me the same old holy grail of cpp errors:
/tmp/ccsh6f87.o: In function `main':
test.cpp:(.text+0x25): undefined reference to `keyop_core::KeyOpCore::KeyOpCore()'
test.cpp:(.text+0x34): undefined reference to `keyop_core::KeyOpCore::~KeyOpCore()'
Update:
as was pointed out by #Danh, there are solutions in the following link:
What is an undefined reference/unresolved external symbol error and how do I fix it?
however, my question is ROS related, I did not write the header files that might cause the problem, and I can't poke around all of the interlinked ones hoping to find a needle in the haystack, I was just hoping someone with background in ROS who had a similar problem might pick this up and point me to their solution.
Thank You.