pFile->ReadString为何会阻塞？肿么办呢

pFile->ReadString为什么会阻塞？肿么办呢？

C/C++ code

pFile = pConn4->OpenRequest(0,url6,NULL,1,NULL,"HTTP/1.1",INTERNET_FLAG_EXISTING_CONNECT|INTERNET_FLAG_NO_AUTO_REDIRECT);      pFile->AddRequestHeaders("Content-Type: application/x-www-form-urlencoded");       pFile->AddRequestHeaders("Accept: */*");       pFile->SendRequest(NULL,0,(LPVOID)(LPCTSTR)str,str.GetLength());text="";    HttpReturn = "";    for(int i=0;pFile->ReadString(text);i++)       {           HttpReturn=HttpReturn+text+"\r\n";       }