http://msdn.microsoft.com/en-us/library/fwkeyyhe.aspx
/WX
Treats all compiler warnings as errors. For a new project, it may be best to use /WX in all compilations; resolving all warnings will ensure the fewest possible hard-to-find code defects.
The linker also has a /WX option. See /WX (Treat Linker Warnings as Errors) for more information.