linker error

Discussion in 'Win32' started by answerme, Mar 11, 2010.

  1. answerme

    answerme New Member

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    I have added two files on my existing mfc application a1.h &a1.cpp . I have function defintion in a1.cpp to read serially. This function iam calling in Scgenview::Ontimer() function in a thread . Below is the code
    Code:
    [B]a1.h [/B]
    int readserial();
    Code:
    [B]a1.cpp[/B]
    #include "stdafx.h"
    #include"a1.h"
    readserial()
    {
    function defintion
    }
    
    Code:
    [B]Scgenview.cpp[/B]
    #include"a1.h"
    #include "stdafx.h"
    void CScenGenView::OnTimer(UINT_PTR nIDEvent)
    {
    
    	LPVOID param= NULL;
    	HANDLE GPS_READ = ::CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)[B]readserial[/B](),(LPVOID) param, 0,NULL);
    	
    }

    But i am getting a linker error which is listed below
    Code:
    Error	41	fatal error LNK1120: 1 unresolved externals	Debug\ScenGen.exe	ScenGen
    
    
    Error	40	error LNK2019: unresolved external symbol "int __cdecl readserial(void)" (?readserial@@YAHXZ) referenced in function "public: void __thiscall CScenGenView::OnTimer(unsigned int)" (?OnTimer@CScenGenView@@QAEXI@Z)	ScenGenView.obj	ScenGen
     
  2. Gene Poole

    Gene Poole New Member

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    I don't know about the first error.

    Your second error is because the function signature for the thread proc is wrong. You need to declare readserial() like this:

    Code:
    DWORD WINAPI readserial(LPVOID lpParameter);
    
     

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