MQL4 Reference File Functions FileWrite

MQL4 Help as One File:


The function is intended for writing of data into a CSV file, delimiter being inserted automatically unless it is equal to 0. After writing into the file, the line end character "\r\n" will be added.

uint  FileWrite(
   int  file_handle,   // File handle
   ...                 // List of recorded parameters



[in]  File descriptor returned by FileOpen().


[in] The list of parameters separated by commas, to write to the file. The number of written parameters can be up to 63.

Return Value

Number of bytes written or 0 in case of error. To obtain information about the error call the GetLastError() function.


Numbers will be converted into a text at output (see the Print() function). Data of the double type are output with the accuracy of 16 digits after the decimal point, and the data can be displayed either in traditional or in scientific format - depending on which format will be the most compact. The data of the float type are shown with 5 digits after the decimal point. To output real numbers with different precision or in a clearly specified format, use DoubleToString().

Numbers of the bool type are displayed as "true" or "false" strings. Numbers of the datetime type are displayed as "YYYY.MM.DD HH:MI:SS".


//|                                               Demo_FileWrite.mq4 |
//|                        Copyright 2014, MetaQuotes Software Corp. |
//|                                     |
#property copyright "Copyright 2014, MetaQuotes Software Corp."
#property link      ""
#property version   "1.00"
#property strict
//--- show the window of input parameters when launching the script
#property script_show_inputs
//--- parameters for receiving data from the terminal
input string             InpSymbolName="EURUSD";      // Сurrency pair
input ENUM_TIMEFRAMES    InpSymbolPeriod=PERIOD_H1;   // Time frame
input int                InpFastEMAPeriod=12;         // Fast EMA period
input int                InpSlowEMAPeriod=26;         // Slow EMA period
input int                InpSignalPeriod=9;           // Difference averaging period
input ENUM_APPLIED_PRICE InpAppliedPrice=PRICE_CLOSE// Price type
//--- parameters for writing data to file
input string             InpFileName="MACD.csv";      // File name
input string             InpDirectoryName="Data";     // Folder name
//| Script program start function                                    |
void OnStart()
   bool     sign_buff[]; // signal array (true - buy, false - sell)
   datetime time_buff[]; // array of signals' appear time
   int      sign_size=0; // signal array size
   double   macd_buff[]; // array of indicator values
   datetime date_buff[]; // array of indicator dates
   int      macd_size=0; // size of indicator arrays
//--- set indexing as time series
//--- reset last error code
//--- copying the time from last 1000 bars
   int copied=CopyTime(NULL,0,0,1000,date_buff);
      PrintFormat("Failed to copy time values. Error code = %d",GetLastError());
//--- prepare macd_buff array
//--- copy the values of main line of the iMACD indicator
   for(int i=0;i<copied;i++)
//--- get size
//--- analyze the data and save the indicator signals to the arrays
   for(int i=1;i<macd_size;i++)
      //--- buy signal
      if(macd_buff[i-1]<0 && macd_buff[i]>=0)
      //--- sell signal
      if(macd_buff[i-1]>0 && macd_buff[i]<=0)
//--- open the file for writing the indicator values (if the file is absent, it will be created automatically)
   int file_handle=FileOpen(InpDirectoryName+"//"+InpFileName,FILE_READ|FILE_WRITE|FILE_CSV);
      PrintFormat("%s file is available for writing",InpFileName);
      PrintFormat("File path: %s\\Files\\",TerminalInfoString(TERMINAL_DATA_PATH));
      //--- first, write the number of signals
      //--- write the time and values of signals to the file
      for(int i=0;i<sign_size;i++)
      //--- close the file
      PrintFormat("Data is written, %s file is closed",InpFileName);
      PrintFormat("Failed to open %s file, Error code = %d",InpFileName,GetLastError());

See also

Comment(), Print(), StringFormat()