.Obj Files as Linker Input
The linker tool (LINK.EXE) accepts .obj files that are in Common Object File Format (COFF).
Remarks
Microsoft provides a complete description of the common object file format. For more information, see PE Format.
Unicode support
Starting with Visual Studio 2005, the Microsoft MSVC 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.
For more information about the compiler and linker, see Unicode Support in the Compiler and Linker. For more information about the Unicode standard, see the Unicode organization.
See also
LINK Input Files
MSVC Linker Options
Support for Unicode
Unicode Support in the Compiler and Linker
Unicode standard
PE Format