/FORCE:{MULTIPLE|UNRESOLVED}
This option tells the linker to create a valid .exe file or DLL even if a symbol is referenced but not defined or is multiply defined.
On the command line, the /FORCE option can take an optional argument:
/FORCE with no arguments implies both multiple and unresolved.
A file created with this option may not run as expected. The linker will not link incrementally when the /FORCE option is specified.
Setting Linker Options | Linker Options | FAQ: Building Your Program