/ZW (Windows Runtime Compilation)
Compiles source code to support Visual C++ component extensions (C++/CX) for the creation of Windows Store apps.
When you use /ZW to compile, always specify /EHsc as well.
When you specify the /ZW option, the compiler supports these features:
The required metadata files, namespaces, data types, and functions that your app requires to execute in the Windows Runtime.
Automatic reference-counting of Windows Runtime objects, and automatic discarding of an object when its reference count goes to zero.
Because the incremental linker does not support the Windows metadata included in .obj files by using the /ZW option, the /Gm (Enable Minimal Rebuild) option is incompatible with /ZW.
For more information, see Visual C++ Language Reference (C++/CX).