Error directive
From cppreference.com
                    
                                        
                    < cpp | preprocessor
                    
                                                            
                    Shows the given error message and renders the program ill-formed.
[edit] Syntax
| #errorerror_message | |||||||||
[edit] Explanation
After encountering the #error directive, an implementation displays the diagnostic message error_message and renders the program ill-formed (the compilation stops). 
error_message can consist of several words not necessarily in quotes.
[edit] See also
| C documentation for Error directive | 


