EXIT_SUCCESS, EXIT_FAILURE

From cppreference.com
< cpplrm; | utilitylrm; | program
Program support utilities
Program termination
(C++11)
(C++11)
EXIT_SUCCESSEXIT_FAILURE
Communicating with the environment
Signals
Signal types
Non-local jumps
Types
Defined in header <cstdlib>
#define EXIT_SUCCESS /*implementation defined*/
#define EXIT_FAILURE /*implementation defined*/

The EXIT_SUCCESS and EXIT_FAILURE macros expand into integral expressions that can be used as arguments to the std::exit function (and, therefore, as the values to return from the main function), and indicate program execution status.

Constant Explanation
EXIT_SUCCESS successful execution of a program
EXIT_FAILURE unsuccessful execution of a program

Notes

Both EXIT_SUCCESS and the value zero indicate successful program execution status (see std::exit), although it is not required that EXIT_SUCCESS equals zero.

See also