MT4 Global String Variables

One major shortfall of Metatrader 4's global variables is they only support doubles. Has anyone come across some code or method for passing Global String Variables between charts/indicators/eas?

I never had the need of this ... not even sure there's a specific function/method to do this ... but you can try to pass your string directly in the GV name.

"EAname_StringName_String" ... then on any chart you look for the GV with the right name+stringname ... and extract the string you are looking for.

Hi PMak,

Have you thought passing them through chart objects ?

I have tried that but when looking for a specific chart using ChartID I found there to be bugs.

For example, if Chart1 has the GV and Chart2 wants to access it, I found that storing Chart1's ChartID as a GV was buggy and for some reason and would often store the wrong ChartID. Perhaps it's fixed with this build, will try again. Or maybe there is a better way to access a chart's object from another chart?

Did you trade on etoro a while back and use the Center of Gravity indicator? I remember talking to a FerruFx on there a long time ago.

Anyways thanks and cheers!

I think that you have to iterate through your charts and on each of them look for an object with a specific name which contains the string you need.

If you talked with a FerruFx on eToro, that wasn't me ...

It was certainly a different instance or maybe a derived object

Hope he is as smart as I am

It's easy to write a smarter one

class SmarterFerruFx : public FerruFx {

};

Sorry, I stop now polluting the thread...

Tried that but accessing the right chart with chartid has been buggy. Will try it again.

I suppose I could cycle thru all charts and then find the one that has the right object.

Great one!

Yes Exactly.

Why don't you try my solution with the GV name ? You set it and it is available for any chart ...

Yes, this should work too. Just be aware that the length must not exceed 63 characters.

i have the same issue but i found a way : why not code your string with a number for example :
HOWDY would be written:

0815230425 (08 15 23 04 25)

of course you have to check the number size to test if there is a zero at the first "char"

with ulong, you can pass string of 10 chars max, though, but you can divide your strings into 2 variables or more, as needed

EDIt : oh it is limited to doubles, so less chars per number, sry

Jeff

I have the same problem and I've been in search of a solution. My code stores the chartID in a GV where the trade was activated and this is needed by other chart EAs to stop monitoring the trade.

The cause of the "bug":
After a bit of hunting down the culprit I've found its caused by the Global Variable having data type DOUBLE and the ChartID() having data type LONG. In the conversion process from Long --> Double --> Long the chart variable can shift by 1. So ChartID() = 130942874255992945 becomes 130942874255992944. Which could feasibly be the next chart. This maybe why there are comments on some forums that ChartID() is unreliable or buggy. A ChartID() variable must be declared as type LONG.

The Global Variable solution:
1. cut up the long type variable & stitch it back together again. Hmm, don't like that one. Messy.
2. Only use the lower 10 digits. That would need conversion to string & cut up & back to DOUBLE. Then I'd need to do the same to ChartID() when testing. Messy.
3. FerruFx : create a global variable using ChartID() as the name (they can be up to 63 characters long) & then test for GVs existence. Plus make sure the GV is deleted when not needed, instead of GV = 0. Sounds very do-able.

Testing solution 3: It works! ...using...

GlobalVariableSet("TradeChartID_"+ChartID(),0); // when a trade is place

if ( GlobalVariableCheck("TradeChartID_"+ChartID()) ) ... // EA checks to see if it initiated the trade or not


Thanks FerruFx