It's simple, simply output text to STDERR containing the string
Your input will be none; however, you should output the message to STDERR.
- Since this is code-golf, the shortest answer wins.
- No standard loopholes please.
- Any method approved by Standard I/O is allowed.
- Your code may not contain the "EOF" that you will output as-is in your error.
- Outputting "EOI" is technically allowed, because the input can also be considered as a separate file.