NULL = any time frame, if you want to check it on the M5 chart then replace NULL with 5, 60 for the H1 chart, etc.
The number after the NULL, is how many bars from the current bar, 0 would be the current bar, 1 would be the previous bar, etc.
Wowser - all great info - and exactly what I was looking for - -thanks so much - however one little item concerned me
Your EA can refer to other symbols but will not receive tick data or any alerts telling you when other (non-attached) symbols are updated.
But I think what I am trying to accomplish will work fine.
Does the above statement mean – for example if attached to a E/U chart - -and G/U tic tic tics away - - since I am attached to the G/U - the EA won’t ‘see’ or register those G/U tics? But once the E/U does its tic - -then it grabs G/U info?
Made sense (despite the typo) and yes means what you said.
Your code is controlled by the ticks coming in on your attached chart.
It’s a mute point for the most part but in theory if your EUR/USD ticks jam up your code does too until they start again.
If the same happens to GBP/USD your EA code will use the '1’s blindly (last closed bar regardless). So if you plan to use real money you want to check the open bar times (at least to the minute) of the bars (previously closed) you are querying and comparing to make sure your checks are on corresponding bars.
Hope that makes sense.
Edited to reduce inconvenience:
iTime(Symbol, Period, Shift) lets you grab the open time.
TimeMinute(iTime(Symbol, Period, Shift)) lets you grab the open minute.
All depends what periods you are comparing.
iTime can be replaced by Time[n] to get open times for current symbol and period EA is attached to where n=0 is the current forming, n=1 is the previously closed.
TimeMinute(Time[n]) would extract the minute.