Returns the spread value of the bar (indicated by the 'shift' parameter) on the corresponding chart.
[in] The symbol name of the financial instrument. NULL means the current symbol.
[in] Period. It can be one of the values of the ENUM_TIMEFRAMES enumeration. 0 means the current chart period.
[in] The index of the received value from the timeseries (backward shift by specified number of bars relative to the current bar).
The function always returns actual data. For this purpose it performs a request to the timeseries for the specified symbol/period during each call. This means that if there is no ready data during the first function call, some time may be taken to prepare the result.
The function does not store previous calls results, and there is no local cache for quick value return.