文件操作

来源：互联网发布：淘宝货到付款拒收后果编辑：程序博客网时间：2024/06/03 20:37

void append(const spi::InternalLoggingEvent& event)
{
  if(!out.good())
  {
   getErrorHandler()->error( LOG4CPLUS_TEXT("file is not open: ")
    + filename);
   return;
  }

  if(out.tellp() >= m_maxFileSize)
  {
   if (!IsDiskNotEnough())
   {// 如果磁盘没有满就新建一个日志文件
    ++m_nLastMaxNo ;
    CreateNewLogFile ();
    layout->formatAndAppend(out, event);

    if(immediateFlush)
    {
     out.flush();
    }
   }
  }
  else
  {
   layout->formatAndAppend(out, event);

   if(immediateFlush)
   {
    out.flush();
   }
  }

}

2.ofstream outfile2("file1", ofstream::out | ofstream::trunc) ;

3.每次写文件不是接着写，而是先清空上一次的再写 ofstream outfile2("file1", ofstream::trunc) ;

4.写字符串 file << stringTemp ; 或者 file << stringTemp.c_str() ;

5.可以向文件六种直接写入数字如： file << 12 << endl ;

6.指定文件的写入位置： ofTemp.seekp(0) ;

7.刷新文件：paraOfstream.flush() ;

8.同时读取两个文件，并读取：

std::streampos posIpTemp = if_IPTemp.tellg() ;
   std::streampos posCityTemp = if_city.tellg() ;
   while (getline(if_IPTemp, strIPTempFrom) && getline(if_city, strCityFrom))
   {
       /*if (strIPTempFrom[0] == '2')
       {
           int k = 0 ;
       }*/
       std::string strCityBigger = strCityFrom.substr(strCityFrom.find("\t") + 1, strCityFrom.rfind("\t") - strCityFrom.find("\t") - 1) ;
       std::string strIPLitter = strIPTempFrom.substr(0, strIPTempFrom.find("\t")) ;

       if (_atoi64(strIPLitter.c_str()) > _atoi64(strCityBigger.c_str()))
       {
           of_city << strCityFrom << "\r\n" ;
           if_IPTemp.seekg(posIpTemp) ;
       }
       else
       {
           of_city << strIPTempFrom << "\r\n" ;
           if_city.seekg(posCityTemp) ;
       }

       posIpTemp = if_IPTemp.tellg() ;
       posCityTemp = if_city.tellg() ;
   }