Intel® oneAPI DPC++/C++ Compiler Developer Guide and Reference
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U
Undefines any definition currently in effect for the specified macro.
Syntax
Linux:  |  
      -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
Alternate Options
None
Example
To undefine a macro, enter the following command:
On Windows systems:
icx /Uia64 prog1.cpp
On Linux systems:
icpx -Uia64 prog1.cpp
If you attempt to undefine an ANSI C macro, the compiler will emit an error:
invalid macro undefinition: <name of macro>