CODEWITHSUNDEEP
c++visual-c++dlllinker-errors
kernel
kernel

Reputation: 346

Linker error when user defined dll is refering another userdefined dll

I was trying to implement a protocol stack using Protocol Layer Design Pattern : http://www.eventhelix.com/realtimemantra/patterncatalog/protocol_layer.htm

In our project,I have all the layers as separate dlls. The layers that i have are:

  1. Application Layer dll

  2. LLC Layer dll

  3. MAC Layer dll

  4. Physical Layer dll

I have another project in the same solution which implements the Design Pattern and has the implementations of the General functionalities of a protocol Layer. All my layers are inheriting from the Protocol Layer Base class. The dependency between projects is as follows: Protocol Layer Design Pattern dll: No dependency Physical Layer dll: Protocol Design Pattern dll MAC Layer dll: Protocol Design Pattern dll and Physical Layer dll LLC Layer dll: Protocol Design Pattern dll and MAC Layer dll Application Layer dll: Protocol Design Pattern dll and LLC Layer dll

Based on the design pattern, each of our layer has pointers to the layer above and below it. And the flow that we designed is like: In application layer constructor we create an object of LLC Layer then LLC Layer creates Mac layer and MAC layer inturn creates physical Layer. They all are linked using pointers.

My Protocol Design Pattern project dll and Physical Layer dll builds properly. But other dll builds are giving linker error. Saying unresolved externals to the constructor of the underlying layer. These are the errors which i am getting.

==================================

  1. 1>phLayer.obj : error LNK2019: unresolved external symbol "public:
    virtual __thiscall CProtocolLayer::~CProtocolLayer(void)"
    (??1CProtocolLayer@@UAE@XZ) referenced in function
    __unwindfunclet$??0CPhysicalLayer@@QAE@PAVCProtocolLayer@@@Z$0 1>phLayer.obj : error LNK2019: unresolved external symbol "public:
    __thiscall CReceiveProtocolHandler::CReceiveProtocolHandler(class CProtocolLayer *)"
    (??0CReceiveProtocolHandler@@QAE@PAVCProtocolLayer@@@Z) referenced in function "public: __thiscall CPhysicalLayer::CPhysicalLayer(class CProtocolLayer *)" (??0CPhysicalLayer@@QAE@PAVCProtocolLayer@@@Z) 1>phLayer.obj : error LNK2019: unresolved external symbol "public: __thiscall CTransmitProtocolHandler::CTransmitProtocolHandler(class CProtocolLayer *)"
    (??0CTransmitProtocolHandler@@QAE@PAVCProtocolLayer@@@Z) referenced in function "public: __thiscall CPhysicalLayer::CPhysicalLayer(class CProtocolLayer *)" (??0CPhysicalLayer@@QAE@PAVCProtocolLayer@@@Z)
    1>phLayer.obj : error LNK2019: unresolved external symbol "public:
    __thiscall CProtocolLayer::CProtocolLayer(class CProtocolLayer *,class CProtocolLayer *)" (??0CProtocolLayer@@QAE@PAV0@0@Z) referenced in function "public: __thiscall
    CPhysicalLayer::CPhysicalLayer(class CProtocolLayer *)"
    (??0CPhysicalLayer@@QAE@PAVCProtocolLayer@@@Z) 1>phLayer.obj : error LNK2019: unresolved external symbol "public: int __thiscall
    CProtocolPacket::getBodyLength(void)"
    (?getBodyLength@CProtocolPacket@@QAEHXZ) referenced in function
    "public: virtual void __thiscall CPhysicalLayer::Data_req(class
    CProtocolPacket *)"
    (?Data_req@CPhysicalLayer@@UAEXPAVCProtocolPacket@@@Z) 1>phLayer.obj : error LNK2019: unresolved external symbol "public: void __thiscall CReceiveProtocolHandler::Handle_Receive(class CProtocolPacket *)"
    (?Handle_Receive@CReceiveProtocolHandler@@QAEXPAVCProtocolPacket@@@Z) referenced in function "private: void __thiscall
    CPhysicalLayer::dataRead(void)" (?dataRead@CPhysicalLayer@@AAEXXZ)
    1>phLayer.obj : error LNK2019: unresolved external symbol "public:
    void __thiscall CProtocolPacket::AddTrailer(int,char *)"
    (?AddTrailer@CProtocolPacket@@QAEXHPAD@Z) referenced in function
    "private: class CProtocolPacket __thiscall
    CPhysicalLayer::convertToProtocolPacket(class
    std::basic_string,class
    std::allocator >)"
    (?convertToProtocolPacket@CPhysicalLayer@@AAE?AVCProtocolPacket@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) 1>phLayer.obj : error LNK2019: unresolved external symbol "public:
    void __thiscall CProtocolPacket::AddHeader(int,char *)"
    (?AddHeader@CProtocolPacket@@QAEXHPAD@Z) referenced in function
    "private: class CProtocolPacket __thiscall
    CPhysicalLayer::convertToProtocolPacket(class
    std::basic_string,class
    std::allocator >)"
    (?convertToProtocolPacket@CPhysicalLayer@@AAE?AVCProtocolPacket@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)

Upvotes: 1

Views: 201

Answers (1)

kris123456
kris123456

Reputation: 501

How are you building the exe? I see that, you are facing only linker issues. Either you must be linking in the wrong order or there must be something, which went wrong. Try to link them in a correct order. This should solve the problem. If not, please provide more information.

Upvotes: 1

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