For the latest documentation on Visual Studio 2017, see Visual Studio 2017 Documentation.
Tells LINK to create a DLL. At the same time, LINK creates an import library, unless an .exp file is used in the build.
The library argument specifies the name of the DLL. You can also use the /OUT linker option to specify the DLL's output name.
The BASE=address argument sets the base address that the operating system uses to load the DLL. This argument overrides the default DLL location of 0x10000000. See the description of the /BASE option for details about base addresses.
Remember to use the /DLL linker option when you build a DLL.