You're reading the documentation for an older, but still supported version (GL013300).
For information on the latest version, please have a look at GL013302.

1.3.2 DRCF Version Compatibility

When there is a #include library function-related header file (DRFL.h), when the compile option is set in C++ language, programming is possible using CDRFLEx class, but when set in C language, a “_function name” type global function should be used for programming.

Some functions may have different interface usage depending on the controller version. Before importing the DRFL header, please declare #define DRCF_VERSION 2 or #define DRCF_VERSION 3 according to the controller version.

Example of including and initializing DRFLEx in C++
 1#ifndef DRCF_VERSION
 2     #define DRCF_VERSION 3  // Set to 3 for DRCF v3
 3#endif
 4#include "../../include/DRFLEx.h"
 5#include "util.hpp"
 6
 7const std::string IP_ADDRESS = "192.168.137.100";
 8
 9using namespace DRAFramework;
10CDRFLEx robot;
11
12bool g_bHasControlAuthority = FALSE;
13bool g_TpInitailizingComplted = FALSE;
14bool control_authority_granted = FALSE;