resource-compiler-error-rc2101.md

description	title	ms.date	f1_keywords	helpviewer_keywords	ms.assetid
Learn more about: Resource Compiler Error RC2101	Resource Compiler Error RC2101	11/04/2016	RC2101	RC2101	580f9d74-162f-41e9-9438-ddbe3457c359

Resource Compiler Error RC2101

Invalid directive in preprocessed RC file

The Resource Compiler file contains a #pragma directive.

Use the #ifndef preprocessor directive with the RC_INVOKED constant that the Resource Compiler defines when it processes an include file. Place the #pragma directive inside a block of code that is not processed when the RC_INVOKED constant is defined. Code in the block is processed only by the C/C++ compiler and not by the Resource Compiler. The following sample code demonstrates this technique:

#ifndef RC_INVOKED
#pragma pack(2)  // C/C++ only, ignored by Resource Compiler
#endif

The #pragma preprocessor directive has no meaning in an .RC file. The #include preprocessor directive is used frequently in an .RC file to include a header file (either a project-based custom header file or a standard header file provided by Microsoft with one of its products). Some of these include files contain the #pragma directive. Because a header file can include one or more other header files, the file that contains the offending #pragma directive may not be immediately obvious.

The #ifndef RC_INVOKED technique can control including header files in project-based header files.