CODEWITHSUNDEEP
c++visual-studiooperator-overloading
JohnCambell
JohnCambell

Reputation: 633

Microsoft Overloading the << Operator Sample throws link errors

I'm trying to compile the Microsoft Sample "Overloading the << Operator for Your Own Classes" but get the following link error:

error LNK1169: one or more multiply defined symbols found

error LNK2005: "class std::basic_ostream > & __cdecl operator<<(class std::basic_ostream > &,class Date const &)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@ABVDate@@@Z) already defined in Date.obj

Anybody any idea why this is not compiling?

Upvotes: 1

Views: 647

Answers (2)

hab
hab

Reputation: 627

For me this error was was related to multiple definitions and i solved it following a recommendation from Microsoft. In project properties=>Linker=>Command Line=> Additional Options text box add a command "/FORCE:MULTIPLE". This solved my problem. (https://msdn.microsoft.com/en-us/library/70abkas3.aspx)

Upvotes: 0

Luchian Grigore
Luchian Grigore

Reputation: 258618

If you have the definition of the operator inside a header file, you have to declare it inline, otherwise it will be defined in all translation units that include that header.

But it's probably better to move it to a implementation file, unless you have strong reasons for having it in a header.

Upvotes: 4

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