/FU (Name Forced #using File)
Gives you a compiler option alternative to passing a file name toin source code.
Specify one file per compiler option.
If you are referencing metadata to use thefeature, you cannot use /FU; you must reference the metadata in code with #using (and the [as_friend] attribute).
Seefor information on how to create an assembly or module for the common language runtime.
To set this compiler option in the Visual Studio development environment
Open the project's Property Pages dialog box. For details, see.
Click the C/C++ folder.
Click the Advanced property page.
Modify the Force #using property.
To set this compiler option programmatically