int CopyOpen	(	string	symbol_name,
		int	timeframe,
		DateTime	start_time,
		int	count,
		out double[]	open_array
	)

Returns into open_array the history data of bar open prices for the selected symbol-period pair in the specified quantity.
It should be noted that elements ordering is from present to past, i.e., starting position of 0 means the current bar

Parameters

symbol	Symbol the data of which should be used to calculate indicator. NULL means the current symbol
timeframe	Timeframe. It can be any of following values: PERIOD_CURRENT 0 Current timeframe PERIOD_M1 1 1 minute PERIOD_M5 5 5 minutes PERIOD_M15 15 15 minutes PERIOD_M30 30 30 minutes PERIOD_H1 60 1 hour PERIOD_H4 240 4 hours PERIOD_D1 1440 1 day PERIOD_W1 10080 1 week PERIOD_MN1 43200 1 month PERIOD_M2 2 2 minutes PERIOD_M3 3 3 minutes PERIOD_M4 4 4 minutes PERIOD_M6 6 6 minutes PERIOD_M10 10 10 minutes PERIOD_M12 12 12 minutes PERIOD_M20 20 20 minutes PERIOD_H2 120 2 hours PERIOD_H3 180 3 hours PERIOD_H6 360 6 hours PERIOD_H8 480 8 hours PERIOD_H12 720 12 hours
start_time	The start time for the first element to copy
count	Data count to copy
open_array	Array of double type

Returns

Returns the number of element in the array or -1 in case of an error.

If the whole interval of requested data is out of the available data on the server, the function returns -1.
If data outside TERMINAL_MAXBARS (maximal number of bars on the chart) is requested, the function will also return -1. If requested timeseries are not yet built or they need to be downloaded from the server, the function will immediately return -1. If you need to return value corresponding to the current uncompleted bar, you can use the first form of call specifying start_pos=0 and count=1. When requesting data by the start date and the number of required elements, only data whose date is less than (earlier) or
equal to the date specified will be returned. It means, the open time of any bar, for which value is returned (volume, spread,
value on the indicator buffer, prices Open, High, Low, Close or open time Time) is always less or equal to the specified one.