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/FU (Name Forced #using File)

A compiler option that you can use as an alternative to passing a file name to #using Directive (C++) in source code.

/FU file


Specifies the metadata file to reference in this compilation.

The /FU switch takes just one file name. To specify multiple files, use /FU with each one.

If you are using C++/CLI and are referencing metadata to use the Friend Assemblies feature, you can't use /FU. You must reference the metadata in code by using #using—together with the [as friend] attribute. Friend assemblies are not supported in Visual C++ component extensions (C++/CX).

For information about how to create an assembly or module for the common language runtime (CLR), see /clr (Common Language Runtime Compilation). For information about how to build in C++/CX, see Building apps and libraries (C++/CX).

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. Select the C/C++ folder.

  3. Select the Advanced property page.

  4. Modify the Force #using property.

To set this compiler option programmatically