C + + error:lnk2005 is already defined in *.obj

Problem

>>: Error lnk2005:xxxx (★★★★) already defined in ※※※.obj

Fatal error LNK1169: find one or more multi-definition symbols

"Possible causes."

When the first. cpp file that uses the header file generates. obj, int i is already defined. When another. cpp that uses this header file is once again [separately] generated. obj, int i is also defined. Then two obj is joined by another. CPP also include this header, and a duplicate definition will appear.

Solution

Typically, this variable is defined in the. h file, moved to a. cpp file, and an extern int ID is added to the CPP file that uses this variable.

C + + error:lnk2005 is already defined in *.obj