Oct 16, 2025 · Learn more about: #error directive (C/C++)The #error directive emits a user-specified error message at compile time. Then it terminates the compilation.

Jul 9, 2023 · 1) After encountering the #error directive, an implementation displays the message diagnostic-message and renders the program ill-formed (the compilation stops).

The directive ‘ #warning ’ is like ‘ #error ’, but causes the preprocessor to issue a warning and continue preprocessing. The tokens following ‘ #warning ’ are used as the warning message.

C Language: #error Directive This C tutorial explains how to use the #error preprocessor directive in the C language.

May 8, 2010 · I am guessing from # that it is only a compile-time utility. How can it be used in C/C++ programs? Did not find much about it on the internet. Any links would be helpful.

Sep 1, 1999 · One of the least used but potentially most useful features of the C preprocessor is the ANSI-specified #error directive. Here's a look at a couple of clever uses for #error that …

Aug 6, 2025 · Your All-in-One Learning Portal: GeeksforGeeks is a comprehensive educational platform that empowers learners across domains-spanning computer science and …

#error "This code should not compile" The #error macro allows you to make compilation fail and issue a statement that will appear in the list of compilation errors.

The #error directive is often used in the #else portion of a #if – #elif – #else construct, as a safety check during compilation. For example, #error directives in the source file can prevent code …

Mar 16, 2011 · What is the use of the #error directive in C? Asked 14 years, 9 months ago Modified 5 years, 4 months ago Viewed 83k times