Export (0) Print
Expand All
Expand Minimize

/U, /u (Undefine Symbols)

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

symbol

The preprocessor symbol to undefine.

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

  1. Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.

  2. Click the C/C++ folder.

  3. Click the Advanced property page.

  4. Modify the Undefine Preprocessor Definitions or Undefine All Preprocessor Definitions properties.

To set this compiler option programmatically

Show:
© 2014 Microsoft