Exit codes

In C++, the exit function is used to terminate the execution of a program. The value supplied as an argument to exit is returned to the operating system as the program's exit code. By convention, a return code of zero means that the program completed successfully.

Here are some of the commonly used exit codes in C++:

• EXIT_SUCCESS: 0, indicates successful termination of the program.
• EXIT_FAILURE: 1, indicates abnormal termination of the program.
• SIGINT: 2, indicates that the program was terminated by a user interrupt (Ctrl+C).
• SIGSEGV: 11, indicates that the program attempted to access a memory location that is not accessible.
• SIGABRT: 6, indicates that the program was aborted by a call to the abort function.
• SIGKILL: 9, indicates that the program was killed by the operating system.

You can also use user-defined exit codes. However, it is important to avoid using the following exit codes, as they have special meanings:

• 1, 2, 126-165, and 255

The exit function is defined in the <stdlib.h> header file.

Here is an example of how to use the exit function:

#include <stdlib.h>

int main() {
    if (some_error_occurred) {
        exit(1); // Terminate the program with an exit code of 1
    }

    // Do something else

    return 0; // Terminate the program with an exit code of 0
}

Example: Using return in main

#include <iostream>

int main() {
    // Some code here...

    if (/*some error condition*/) {
        std::cout << "An error occurred." << std::endl;
        return 1;
    }

    // More code here...

    if (/*another error condition*/) {
        std::cout << "Another error occurred." << std::endl;
        return 2;
    }

    return 0; // Successful execution
}