C++ DLL奇怪的问题

LandyTan 2018-11-13 06:01:22

#ifdef MYSQL_EXPORTS

#define MYSQL_API __declspec(dllexport)

#else

#define MYSQL_API __declspec(dllimport)

#endif

h文件中使用以上代码就报错，使用以下代码就没问题

#ifdef SQLSERVER_EXPORTS

#define MYSQL_API __declspec(dllexport)

#else

#define MYSQL_API __declspec(dllimport)

#endif

报错内容：
1>error LNK2019: 无法解析的外部符号 "__declspec(dllimport) const CSqlObject::`vftable'" (__imp_??_7CSqlObject@@6B@)，该符号在函数 "public: __cdecl CSqlObject::CSqlObject(void)" (??0CSqlObject@@QEAA@XZ) 中被引用
1> error LNK2019: 无法解析的外部符号 "__declspec(dllimport) const CSQLPcm::`vftable'" (__imp_??_7CSQLPcm@@6B@)，该符号在函数 "public: __cdecl CSQLPcm::CSQLPcm(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (??0CSQLPcm@@QEAA@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) 中被引用
1>fatal error LNK1120: 2 个无法解析的外部命令

麻烦各位大佬帮忙看一下，谢谢！
完整代码：

.h

#ifdef MYSQL_EXPORTS

#define MYSQL_API __declspec(dllexport)

#else

#define MYSQL_API __declspec(dllimport)

#endif



#include <WinSock2.h>

#include <iostream>

#include <string>

#include <list>

#include <tuple>

#include "mysql.h"

using namespace std;



#pragma comment(lib, "libmysql.lib")

#pragma warning(disable:4267)

#define cstring const string 



enum PCM_PRODUCT

{

	LOGIN,

	PASSWORD,

	PHONE

};

class MYSQL_API CSqlObject

{

public:

	CSqlObject();

	virtual ~CSqlObject();



public:

	string GetErrorDesc();

	int GetErrorID();

	bool Connect(__in string szIpAddr, __in unsigned int unPort,

		__in string szUser, __in string szPass, __in string szDatabase);

	bool Command(__in string szComm);

	virtual bool Result(__out string **pOutBuf, __out int *pNum, __in string symbol = "\t");

	int Encrypt(__inout char* pInOut, __in int len);

	int Decrypt(__inout char* pInOut, __in int len);

	int RecordMemoryAddr(__in const char* pString, __in int len, __out char** pOut);

	int ReductionMemoryAddr(__in const char* pInHex, __in int len, __out char** pOut);

	tuple<int, string*> Split(__in string Value, __in string symbol);

protected:

	MYSQL *m_pMySQL;

	int m_nErrorID;

};



class MYSQL_API CSQLPcm : public CSqlObject

{

public:

	CSQLPcm(cstring _user = "");

	inline cstring GetUser()const;

	inline void SetUser(cstring _user);



public:

	list<void*>* Result(PCM_PRODUCT Pro);

	list<void*>* Select(PCM_PRODUCT Pro, cstring _cszWhileValue = "");

	list<void*>* Select(PCM_PRODUCT Pro, void* _pPhone);

	bool Add(PCM_PRODUCT Pro, void* _pPhone);

	bool Update(PCM_PRODUCT Pro, void* _pPhone1, void* _pPhone2);

	bool Delete(PCM_PRODUCT Pro, void* _pPhone);

private:

	string m_szUserId;

};

.cpp

#include "stdafx.h"

#include "CMySQL.h"

#include <queue>

using namespace std;





CSqlObject::CSqlObject()

	:m_nErrorID(0)

	, m_pMySQL(new MYSQL){}



CSqlObject::~CSqlObject(){}



bool CSqlObject::Connect(__in string szIpAddr, __in unsigned int unPort,

	__in string szUser, __in string szPass, __in string szDatabase){return true;}



bool CSqlObject::Command(__in string szComm){return true;}



bool CSqlObject::Result(__out string **pOutBuf, __out int *pNum, __in string symbol){return true;}



string CSqlObject::GetErrorDesc(){return "";}



int CSqlObject::GetErrorID(){return 0;}



tuple<int, string*> CSqlObject::Split(__in string Value, __in string symbol){return make_tuple(0, (string*)NULL);}



int CSqlObject::Encrypt(char* pInOut, int len){return 0;}



int CSqlObject::Decrypt(char* pInOut, int len){return 0;}



int CSqlObject::RecordMemoryAddr(const char* pString, int len, char** pOut){return 0;}



int CSqlObject::ReductionMemoryAddr(const char* pInHex, int len, char** pOut){return 0;}



//////////////////////////////////////////////////////////



CSQLPcm::CSQLPcm(cstring _user)

	:m_szUserId(_user){}



cstring CSQLPcm::GetUser()const{return "";}



void CSQLPcm::SetUser(cstring _user){}



list<void*>* CSQLPcm::Result(PCM_PRODUCT Pro){return NULL;}



list<void*>* CSQLPcm::Select(PCM_PRODUCT Pro, cstring _cszWhileValue){return NULL;}



list<void*>* CSQLPcm::Select(PCM_PRODUCT Pro, void* Param){return NULL;}



bool CSQLPcm::Add(PCM_PRODUCT Pro, void* Param){return true;}



bool CSQLPcm::Update(PCM_PRODUCT Pro, void* Param1, void* Param2){return true;}



bool CSQLPcm::Delete(PCM_PRODUCT Pro, void* Param){return true;}