Customizing C++ Command-Line Processing
If your program does not take command-line arguments, you can save a small amount of space by suppressing use of the library routine that performs command-line processing. This routine is called _setargv and is described in Wildcard Expansion. To suppress its use, define a routine that does nothing in the file containing the main function, and name it _setargv. The call to _setargv is then satisfied by your definition of _setargv, and the library version is not loaded.
Similarly, if you never access the environment table through the envp argument, you can provide your own empty routine to be used in place of _setenvp, the environment-processing routine. Just as with the _setargv function, _setenvp must be declared as extern "C".
Your program might make calls to the spawn or exec family of routines in the C run-time library. If this is the case, you should not suppress the environment-processing routine, since this routine is used to pass an environment from the parent process to the child process.