CStdioFile mFile;
  CFileException  mExcept;
  CString strout,tmp,tmp1;
  int strpos=0;
     mFile.Open("c:\\msg.txt", CFile::modeWrite, &mExcept);
  CString strin="sMSG00000001\n0000|0001:100\n0000|0003:200\n";
  mFile.WriteString(strin);
  strin="MSG00000002\n0000|0002:100\n";
  mFile.WriteString(strin);
  mFile.Close();
   CFile file("c:\\msg.txt",CFile::modeNoTruncate|CFile::modeReadWrite);
  char *pBuf=new char[file.GetLength()+1];
  ZeroMemory(pBuf,file.GetLength()+1);  
  file.Read(pBuf,file.GetLength());
  tmp=pBuf;
  while(tmp.Find("MSG",strpos)+1)
  {
  strpos=tmp.Find("MSG",strpos+1);
  tmp1="";

  }
  file.Close();

  mFile.Open("c:\\msg.txt", CFile::modeReadWrite, &mExcept);  

  while(mFile.ReadString(strout))
  {
   if(!strout.Find("MSG",0))
   {
   tmp=strout;
   }
   else
   {
   tmp1=strout;

   }

  }