.Obj Files as Linker Input
The linker tool (LINK.EXE) accepts .obj files that are in Common Object File Format (COFF).
Microsoft provides a downloadable document that defines the common object file format. For more information, download revision 8.1 or later of the Microsoft Portable Executable and Common Object File Format Specification.
Starting with Visual Studio 2005, the Microsoft Visual C++ compiler supports Unicode characters in identifiers as defined by the ISO/IEC C and C++ standards. Previous versions of the compiler supported only ASCII characters in identifiers. To support Unicode in the names of functions, classes, and statics, the compiler and linker use the Unicode UTF-8 encoding for COFF symbols in .obj files. The UTF-8 encoding is upwardly compatible with the ASCII encoding used by earlier versions of Visual Studio.