Example of using readlink to get directory of executable.

readlink_example.cc

#include <unistd.h>
#include <boost/filesystem.hpp>
namespace fs = boost::filesystem;
  
// Get directory of executable (<base_dir>).
char exe_str[200];
readlink("/proc/self/exe", exe_str, 200);
fs::path exe_path(exe_str);
std::string base_dir = exe_path.parent_path().string();

// Use <base_dir> to load a file using relative path to executable.
cv::Mat truth = cv::imread(base_dir + "/../mlm_test_images/RasterizationTest_DrawLineInterpolatedTest.png",