Linker Tools Error LNK2005
symbol already defined in object
The given symbol, displayed in its decorated form, was multiply defined.
Accidentally linking with both the single-threaded and multithreaded libraries. Ensure that the application project file includes only the appropriate libraries and that any third-party libraries have appropriately created single-threaded or multithreaded versions.
Mixing static and dynamic libraries when also using /clr.
The symbol is a packaged function (created by compiling with /Gy) and was included in more than one file but was changed between compilations. Recompile all files that include symbol.
The symbol is defined differently in two member objects in different libraries, and both member objects were used.
An absolute is defined twice, with a different value in each definition.
A header file declared and defined a variable. Possible solutions include:
Declare the variable in .h: extern BOOL MyBool; and then assign to it in a .c or .cpp file: BOOL MyBool = FALSE;.
Declare the variable static.
Declare the variable selectany.
If you use uuid.lib in combination with other .lib files that define GUIDs (for example, oledb.lib and adsiid.lib). For example:
oledb.lib(oledb_i.obj) : error LNK2005: _IID_ITransactionObject
already defined in uuid.lib(go7.obj)
To fix, add /FORCE:MULTIPLE to the linker command line options, and make sure that uuid.lib is the first library referenced.
More information look here:http://msdn.microsoft.com/en-us/library/72zdcz6f%28v=vs.71%29.aspx