/Za, /Ze (Disable Language Extensions)

 

For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

The /Za compiler option emits an error for language constructs that are not compatible with ANSI C89 or ISO C++11. The /Ze compiler option, which is on by default, enables Microsoft extensions.

/Za  
/Ze  

System_CAPS_ICON_note.jpg Note

The /Ze option is deprecated because its behavior is on by default. We recommend you use the /Zc (Conformance) compiler options to control specific language extension features. For a list of deprecated compiler options, see the Deprecated and Removed Compiler Options section in Compiler Options Listed by Category.

The Visual C++ compiler offers a number of features beyond those specified in either the ANSI C89, ISO C99, or ISO C++ standards. These features are known collectively as Microsoft extensions to C and C++. These extensions are available by default, and not available when the /Za option is specified. For more information about specific extensions, see Microsoft Extensions to C and C++.

We recommend that you disable language extensions by specifying the /Za option if you plan to port your program to other environments. When /Za is specified, the compiler treats Microsoft extended keywords as simple identifiers, disables the other Microsoft extensions, and automatically defines the __STDC__ predefined macro for C programs.

Other compiler options used with /Za can affect how the compiler ensures standards conformance. For example, /Za and /fp (Specify Floating-Point Behavior) may result in floating-point type promotion behavior that does not conform to the ISO C99 or C++11 standards.

For ways to specify specific standards-conformant behavior settings, see the /Zc compiler option.

For more information about conformance issues with Visual C++, see Nonstandard Behavior.

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. In the navigation pane, choose Configuration Properties, C/C++, Language.

  3. Modify the Disable Language Extensions property.

To set this compiler option programmatically

Compiler Options
Setting Compiler Options
/Zc (Conformance)

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