hash-error-directive-c-cpp.md

title	ms.date	f1_keywords	helpviewer_keywords	ms.assetid
#error directive (C/C++)	08/29/2019	#error	#error directive preprocessor, directives error directive (#error directive)	d550a802-ff19-4347-9597-688935d23b2b

#error directive (C/C++)

The #error directive emits a user-specified error message at compile time, and then terminates the compilation.

Syntax

#error token-string

Remarks

The error message that this directive emits includes the token-string parameter. The token-string parameter is not subject to macro expansion. This directive is most useful during preprocessing, to notify the developer of a program inconsistency, or the violation of a constraint. The following example demonstrates error processing during preprocessing:

#if !defined(__cplusplus)
#error C++ compiler required.
#endif

See also

Preprocessor directives