Trying to understand the second form of IsTradeAllowed?

[stanf6499]

Please see the script below:

void OnStart()

  {

   Alert(Symbol());

   Alert(IsTradeAllowed(NULL, TimeGMT()));

   Alert(IsTradeAllowed(Symbol(), TimeGMT()));

   Alert(IsTradeAllowed("GBPUSD", TimeGMT()));

  }

It returns: EURUSD true false false.  Why does it not return:  URUSD true true true.  I tried it at breakfast; lunch; dinner and supper today and got the same results each time.

Also what does null mean (I believe it means the chart selected in MT4 is used, but I am looking at the GBPUSD chart in MT4)? I have read the docs here:  IsTradeAllowed - Checkup - MQL4 Reference , which didn't really help.

I realise   IsTradeAllowed (with no arguements) checks that AutoTrading is enabled.

[stanf6499]

Update 04/03/21 at 19:55

I have now discovered that if I right click on the Market Watch and select: show all, then more symbols appear. I can then see that some symbols are greyed out and some symbols are not. The symbols that are not greyed out e.g. USDGBP-g return what I would expect when running the program above i.e. alert 1-alert 4 =true. The symbols that are greyed out e.g. USDGBP returns true; true; false; false in the program above. I now have two questions:

1. Why does:  IsTradeAllowed(NULL, TimeGMT()); //alert 2  return true for symbols that are greyed out?

2. What does -g mean in GBPUSD-g?

My broker is Oanda.

[Keith Watford]

Where in the documentation does it state that you can use NULL?