Reading XGBoost Model in C++

I trained my model in R using XGBoost and now need to do predictions in C++. I am trying to load the model file in C++ using XGBoosterLoadModel function.

My code compiles fine but it fails at discovering my unit-test functions. When I remove the call to function XGBoosterLoadModel, everything works fine and I can see my unit tests.

Here's what I have in my unit test file. Any clue on what I'm missing would be really appreciated:

    #include <xgboost/c_api.h>
    #include "stdafx.h"
    #include <google/gtest/gtest.h>

    namespace UnitTests
    {
        TEST(XGBoost, HysteresisPeakDetection_WithEmptyInput_ReturnsFalse)
        {
            const char *fname;
            BoosterHandle handle;

            int a = XGBoosterLoadModel(handle, fname);
        }
    }