/experimental:preprocessor (Enable preprocessor conformance mode)

This option is obsolete starting in Visual Studio 2019 version 16.5, replaced by the /Zc:preprocessor compiler option. /experimental:preprocessor enables an experimental, token-based preprocessor that more closely conforms to C++11 standards, including C99 preprocessor features. For more information, see MSVC new preprocessor overview.




Use the /experimental:preprocessor compiler option to enable the experimental conforming preprocessor. You can use /experimental:preprocessor- option to explicitly specify the traditional preprocessor.

The /experimental:preprocessor option is available starting in Visual Studio 2017 version 15.8. Starting in Visual Studio 2019 version 16.5, the new preprocessor is complete, and available under the /Zc:preprocessor compiler option.

To set this compiler option in the Visual Studio development environment

  1. Open the project's Property Pages dialog box. For details, see Set C++ compiler and build properties in Visual Studio.

  2. Select the Configuration Properties > C/C++ > Command Line property page.

  3. Modify the Additional Options property to include /experimental:preprocessor and then choose OK.

See also

/Zc (Conformance)