程序出现c2039错误，求解决啊。。

2012-06-22 10:04:21 316 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

C2039错误解析：如何解决std::mutex的缺失问题本文深入解析C++编程中常见的C2039错误，特别是‘std::mutex’缺失问题的根源与解决方案。核心原因包括未包含头文件、编译器未启用C++11及以上标准、环境配置不当或编译器版本过旧。文章提供了从基础排查到环境配置的完整修复指南，并探讨了在无法升级环境时的替代方案，帮助开发者彻底解决这一多线程编程中的典型编译错误。阅读详情

STDMETHODIMP CQuestion::GetQuestion(int x_nType, int x_nQID, BSTR *x_QInfo)
{
// TODO: Add your implementation code here
try
{

if (FAILED(pConn.CreateInstance(__uuidof(Connection))))
{
*x_QInfo = ::SysAllocString(L"N#Couldn't create connection component!");
return S_OK;
}

if (FAILED(pConn->Open("Provider=MSDASQL.1;Password=;Persist Security Info=True;User ID=SA;Data Source=EXAM;Initial Catalog=EXAM","","",-1)))
{
*x_QInfo = ::SysAllocString(L"N#Couldn't open connection!");
return S_OK;
}

CComBSTR m_bstrSql;

switch(x_nType)
{
case 0:
m_bstrSql.Append("SELECT * FROM LOGIC WHERE QID=");
break;
case 1:
m_bstrSql.Append("SELECT * FROM SINGLE WHERE QID=");
break;
case 2:
m_bstrSql.Append("SELECT * FROM MULTIPLY WHERE QID=");
break;
default:
*x_QInfo = ::SysAllocString(L"N#Type error!");
return S_OK;
break;
}

char m_strBuf[10];
_itoa(x_nQID, m_strBuf, 10);

m_bstrSql.Append(m_strBuf);

_bstr_t m_bstrResult(m_bstrSql,FALSE);

CComVariant m_varNum;

pRs = pConn->Execute(m_bstrResult, &m_varNum, -1);

if (pRs->ADOEOF)//出现error C2039: 'ADOEOF' : is not a member of '_Recordset'
{
*x_QInfo = ::SysAllocString(L"N#Couldn't find records!");
return S_OK;
}

CComVariant m_varData;
CComBSTR m_bstrInfo;
m_bstrInfo.Append("Y#");

char m_strFieldName[20];

pRs->GetFields()->GetItem("CONTENT")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{
m_bstrInfo.AppendBSTR(m_varData.bstrVal);
m_bstrcontent.AppendBSTR(m_varData.bstrVal);
}

m_bstrInfo.Append("#");

if (x_nType >= 1)
{
pRs->GetFields()->GetItem("ANSWERA")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{
m_bstrInfo.AppendBSTR(m_varData.bstrVal);
m_bstrQ1.AppendBSTR(m_varData.bstrVal);
}
m_bstrInfo.Append("#");

pRs->GetFields()->GetItem("ANSWERB")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{
m_bstrInfo.AppendBSTR(m_varData.bstrVal);
m_bstrQ2.AppendBSTR(m_varData.bstrVal);
}

m_bstrInfo.Append("#");

pRs->GetFields()->GetItem("ANSWERC")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{
m_bstrInfo.AppendBSTR(m_varData.bstrVal);
m_bstrQ3.AppendBSTR(m_varData.bstrVal);
}

m_bstrInfo.Append("#");

pRs->GetFields()->GetItem("ANSWERD")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{
m_bstrInfo.AppendBSTR(m_varData.bstrVal);
m_bstrQ4.AppendBSTR(m_varData.bstrVal);
}

}
m_bstrInfo.Append("#");

if (x_nType == 2)
{
pRs->GetFields()->GetItem("ANSWERA")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{
m_bstrInfo.AppendBSTR(m_varData.bstrVal);
m_bstrQ5.AppendBSTR(m_varData.bstrVal);
}
}
pRs->GetFields()->GetItem("ANSWER")->get_Value(&m_varData);
if(m_varData.vt != VT_NULL)
{

m_shortAnswer=m_varData.intVal;
}

*x_QInfo = m_bstrInfo;
}
catch(...)
{
*x_QInfo = ::SysAllocString(L"Error occurs!");
return S_OK;

}

return S_OK;
}

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