Um, this might be simple, but...do you have a GVf.dll file in the "External Function DLLs" folder?

2. The 2nd item should be GetVar, with an "R", not GetVal with an "L".

Roy -- In his example, it looks the Chart Indicator is called first, then the Expert.

So...which gets executed first?


--Johnathan

Hi Roy & Johnathan

Correcting the spelling did the trick, but I've ran into anthor error problem. This time using the global variable to get Custom Indicator Gobal Bestup to reference its parameter from Custom Indicator Bands, I got the error message "This variable or expression must contain only constant data". Where have I gone wrong.

{Bands}

x:=Input("Short Term Moving Average",7,14,7);
y:=Input("Envelopes Percentage variation",1,99,5)/100;
a:=x*5;

STMA:=Mov(C,x,E);
UB:=Mov(C,x,S)*(1+y);
LB:=Mov(C,x,S)*(1-y);
LTMA:=Mov(C,a,E);

STMA;
UB;
LB;
LTMA;

{Gobal Variable}

I:=ExtFml("GVf.SetVar","Gx",x);
I:=ExtFml("GVf.SetVar","Gy",y*100);

{Gobal Bsetup}

Gx:=ExtFml("GVf.GetVar","Gx");
y:=5/100;

EMA:=Mov(C,Gx,E);
UB:=Mov(C,Gx,S)*(1+y);
LB:=Mov(C,Gx,S)*(1-y);
lta:=Mov(C,Gx*5, S); {Long term average}

I am also having diffculty understand the idea "Before calling a global variable from the GlobalVar DLL (or any copy of it by another name) that variable must be populated with the correct data array values". In your example you have variable Eq, I don't understant what variable I would use in my case.

Gregor

Hi Gregor Your "Gx" variable must provide a value that MetaStock accepts as a "constant", and enclosing it in LastValue() does that for you. {Gobal Bsetup} Gx:=LastValue(ExtFml("GVf.GetVar","Gx")); y:=5/100; EMA:=Mov(C,Gx,E); UB:=Mov(C,Gx,S)*(1+y); LB:=Mov(C,Gx,S)*(1-y); lta:=Mov(C,Gx*5, S); {Long term average} Re your other difficulty, if a global variable is called by an expert or an exploration and the indicator generating that global variable is NOT plotted on the current chart then the required global variable may not exist as a viable data array. It's only when you plot the custom indicator on a chart or call it in the expert (or exploration) that the GV SetVar function creates or refreshes the "Gx" and "Gy" global variables. Having your custom indicator present in the Indicator Builder but not called by a chart, expert or exploration means that MetaStock will not run the necessary sequence of code to generate the appropriate GV data arrays (Gx, Gy etc.). Once a custom indicator creates a set of global variables, those global variables remain constant until the generating indicator is plotted on another chart or called for another security. All global variables are lost when when MetaStock closes. Restarting MetaStock does not automatically generate any global variables - that will not and cannot occur until the MetaStock executes (calls, runs or whatever term you like to use) the indicator that generates the required global variables. Copying code created by someone else is a good way to get started with global variables, but understand that a global variable must be created before it can be used. Having the code in an indicator is only the first step - the indicator must be processed by MetaStock for it to create its global variables. Roy