The /U compiler option undefines the specified preprocessor symbol. The /u compiler option undefines the Microsoft-specific symbols that the compiler defines.
/U[ ]symbol
/u
Arguments
- symbol
The preprocessor symbol to undefine.
Remarks
Neither the /U or /u option can undefine a symbol created by using the #define directive.
The /U option can undefine a symbol that was previously defined by using the /D option.
By default, the compiler defines the following Microsoft-specific symbols.
Symbol |
Function |
|---|---|
_CHAR_UNSIGNED |
Default char type is unsigned. Defined when the /J option is specified. |
_CPPRTTI |
Defined for code compiled with the /GR option. |
_CPPUNWIND |
Defined for code compiled with the /EHsc option. |
_DLL |
Defined when the /MD option is specified. |
_M_IX86 |
By default, defined to 600 for x86 targets. |
_MSC_VER |
For more information, see Predefined Macros. |
_WIN32 |
Defined for WIN32 applications. Always defined. |
_MT |
Defined when the /MD or /MT option is specified. |
To set this compiler option in the Visual Studio development environment
Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.
Click the C/C++ folder.
Click the Advanced property page.
Modify the Undefine Preprocessor Definitions or Undefine All Preprocessor Definitions properties.
To set this compiler option programmatically
See Also
Reference
/J (Default char Type Is unsigned)
/GR (Enable Run-Time Type Information)