Shared file read/write error

[Yuan Shan Yao]

 void WriteToCsvFile(string file_name)
  {
   int filehandle=FileOpen(file_name,FILE_WRITE|FILE_CSV|FILE_COMMON,'*');
   if(filehandle!=INVALID_HANDLE)
     {
      FileWrite(filehandle,_Symbol);
      FileClose(filehandle);
      Print("FileOpen OK");
     }
  }
string  ReadFromCsvFile(string file_name)
  {
   int filehandle=FileOpen(file_name,FILE_READ|FILE_CSV|FILE_COMMON,'*');
   string strread = "";
   if(filehandle!=INVALID_HANDLE)
     {
      strread = FileReadString(filehandle);
      FileClose(filehandle);
     }

return  strread ;
}

Example:

1. Use WriteToCsvFile("fractals_mql4.csv") in MT4. Use ReadFromCsvFile ("fractals_mql4.csv") in MT4; Read data correctly

2. Use WriteToCsvFile("fractals_mql4.csv") in MT4; Use ReadFromCsvFile ("fractals_mql4.csv") in MT5; Read data error

3. Use WriteToCsvFile("fractals_mql5.csv") in MT5; Use ReadFromCsvFile ("fractals_mql5.csv") in MT4; Read data correctly

3. Use WriteToCsvFile("fractals_mql5.csv") in MT5; Use ReadFromCsvFile ("fractals_mql5.csv") in MT5; Read data correctly

Why is it wrong to write files in MT4 and read files in MT5? The content of the analysis file is inconsistent, how to solve it without using an external DLL?