OnStart

The function is called in scripts and services when the Start event occurs. The function is intended for one-time execution of actions implemented in a program. There are two function types.

The version that returns the result

int OnStart(void);

Return Value

The value of int type displayed in the Journal tab.

The entry "script script_name removed (result code N)" is created in the terminal journal after a script execution is complete. Here N is a value returned by the OnStart() function.

The entry "service service_name stopped (result code N)" is created in the terminal journal after a service execution is complete. Here N is a value returned by the OnStart() function.

The OnStart() call that returns the execution result is recommended for use since it not only allows for a script or service execution, but also returns an error code or other useful data to analyze the program execution result.

The version without a result return is left only for compatibility with old codes. It is not recommended for use

void OnStart(void);

Note

OnStart() is the only function for handling events in scripts and services. No other events are sent to these programs. In turn, the Start event is not passed to EAs and custom indicators.

Sample script:

//--- macros for working with colors
#define XRGB(r,g,b)    (0xFF000000|(uchar(r)<<16)|(uchar(g)<<8)|uchar(b))
#define GETRGB(clr)    ((clr)&0xFFFFFF)
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//--- set a downward candle color
   Comment("Set a downward candle color");
   ChartSetInteger(0,CHART_COLOR_CANDLE_BEAR,GetRandomColor());
   ChartRedraw(); // update the chart immediately without waiting for a new tick
   Sleep(1000);   // pause for 1 second to see all the changes
//--- set an upward candle color
   Comment("Set an upward candle color");
   ChartSetInteger(0,CHART_COLOR_CANDLE_BULL,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set the background color
   Comment("Set the background color");
   ChartSetInteger(0,CHART_COLOR_BACKGROUND,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of Ask line
   Comment("Set color of Ask line");
   ChartSetInteger(0,CHART_COLOR_ASK,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of Bid line
   Comment("Set color of Bid line");
   ChartSetInteger(0,CHART_COLOR_BID,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of a downward bar and a downward candle frame
   Comment("Set color of a downward bar and a downward candle frame");
   ChartSetInteger(0,CHART_COLOR_CHART_DOWN,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of a chart line and Doji candlesticks
   Comment("Set color of a chart line and Doji candlesticks");
   ChartSetInteger(0,CHART_COLOR_CHART_LINE,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of an upward bar and an upward candle frame
   Comment("Set color of an upward bar and an upward candle frame");
   ChartSetInteger(0,CHART_COLOR_CHART_UP,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of axes, scale and OHLC line
   Comment("Set color of axes, scale and OHLC line");
   ChartSetInteger(0,CHART_COLOR_FOREGROUND,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set a grid color
   Comment("Set a grid color");
   ChartSetInteger(0,CHART_COLOR_GRID,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set Last price color
   Comment("Set Last price color");
   ChartSetInteger(0,CHART_COLOR_LAST,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of Stop Loss and Take Profit order levels
   Comment("Set color of Stop Loss and Take Profit order levels");
   ChartSetInteger(0,CHART_COLOR_STOP_LEVEL,GetRandomColor());
   ChartRedraw();
   Sleep(1000);
//--- set color of volumes and market entry levels
   Comment("Set color of volumes and market entry levels");
   ChartSetInteger(0,CHART_COLOR_VOLUME,GetRandomColor());
   ChartRedraw();
  }
//+------------------------------------------------------------------+
//| Return a randomly generated color                                |
//+------------------------------------------------------------------+
color GetRandomColor()
  {
   color clr=(color)GETRGB(XRGB(rand()%255,rand()%255,rand()%255));
   return clr;
  }