The DB2CLI_VER define allows the application to specify that the DB2 CLI header files are to remain compatible with previous versions of DB2 CLI.
DB2CLI_VER must be set to a hex value either as a compile flag, or as a #define before the DB2 CLI header files are included. For example, using the -D compiler flag:
-DDB2CLI_VER=0x0110sets the DB2CLI_VER to Version 1.1.
In Version 2.1, if DB2CLI_VER is not defined it defaults to 0x0210.