Exit Status / Exit Codes

return a non-zero number from main() to indicate that there was an error. This means that you have 4 billion possible error codes.

• If you don’t return a value explicitly, the exit code will be 0.

Example:

int main(int argc, string argv[])
{
    if (argc != 2)
    {
        printf("missing args", argv[1]);
        return 1;
    }
    printf("hello, %s\n", argv[1]);
    return 0;
}