Intel® C++ Compiler 16.0 User and Reference Guide

U

Undefines any definition currently in effect for the specified macro.

Syntax

Linux and OS X:

-Uname

Windows:

/Uname

Arguments

name

Is the name of the macro to be undefined.

Default

OFF

Macro definitions are in effect until they are undefined.

Description

This option undefines any definition currently in effect for the specified macro. It is equivalent to an #undef preprocessing directive.

On Windows systems, use the /u option to undefine all previously defined preprocessor values.

IDE Equivalent

Visual Studio: Preprocessor > Undefine Preprocessor Definitions

Eclipse: Preprocessor > Undefine Preprocessor Definitions

Xcode: Preprocessor > Undefine Preprocessor Definitions

Alternate Options

None

Example

To undefine a macro, enter the following command:

On Windows* systems:

icl -Uia32 prog1.cpp

On Linux* systems:

icpc -Uia32 prog1.cpp

On OS X* systems:

icl++ -Uia32 prog1.cpp
icpc -Uia32 prog1.cpp

If you attempt to undefine an ANSI C macro, the compiler will emit an error:

invalid macro undefinition: <name of macro>