std::string operator , (const std::string& s1, const char* s2)
{
  return s1 + s2;
}

std::string operator , (const char* s1, const std::string& s2)
{
  return s1 + s2;
}

#define TO_STRING_I(n) #n
#define TO_STRING(n) TO_STRING_I(n)
#define FILEPOS __FILE__ "(" TO_STRING(__LINE__) "): "
#define THROW_IF(cond, type, msg, ...) if (cond) throw type((FILEPOS + std::string(msg), __VA_ARGS__))

struct fatal_error : public std::runtime_error
{
    fatal_error(char const* errormsg)
      : std::runtime_error(std::move(errormsg))
  {}
  fatal_error(std::string errormsg)
      : std::runtime_error(std::move(errormsg))
  {}
};

inline std::vector<char> read_file(char const* filename)
{
  std::ifstream file(filename, std::ios::binary);
  THROW_IF(!file, fatal_error, "Could not open file: ", filename);
  file.seekg(0, std::ios::end);
  std::vector<char> buf(static_cast<std::vector<char>::size_type>(file.tellg()));
  file.seekg(0, std::ios::beg);
  file.read(&buf[0], buf.size());
  THROW_IF(!file, fatal_error, "Could not read file: ", filename);
  return buf;
}

int main()
{
  try
  {
    auto buf = read_file("testasfsfadf.txt");
    buf.push_back(0);
    std::cout << &buf[0];
  }
  catch (std::runtime_error& e)
  {
    std::cout << e.what() << '\n';
  }
}