Global Vs. Public Variable.

[Evagrius Ponticus]

Hello,

Can anyone please explain the difference between declaring a variable as global or as public. Aren't they both available to the entire project including forms? Thank you.

 

[Jeffrey Smith]

When you Dim a variable inside a Sub or Function, it is only available to that Sub or Function. Making a variable Public makes it available to all Subs and Functions within that Module. I'm not sure if it's available to all modules; it could easily be tested.

Jeff

 

[Evagrius Ponticus]

Yes - if it's a Global variable it is available to all subs - but that seems to be the case for Public variables as well - so I am not sure of the difference.

 

[mikerickson]

In VBA there are three levels of scope.

Local: the variable is declared inside a Sub or Function, using the Dim or Static keyword and is only availible inside that procedure.

Sub myRtn()
Dim myVariable as Variant
...

Module-wide: the variable is declared at the beginning of the module with the Dim keyword. it is available ot all procedures in that module, but not to procedures in other modules

Dim myModVariable as String

Sub myFirstProceedure
...

Public - the variable is declared at the beginning of a normal module with the Public key word. It is avaliable to all procedures is all modules of that project. (Variables declared with Public in Class, Userform and Object code modules have specialized meanings.)

Public myPublicVariable as String

Sub myFirstProceedure
...

Global is not a VBA reserved word. There are no (uppercase) Global variables in VBA. "global" is a term in the meta-language of programming, not in the programming language VBA.

 

[Jeffrey Smith]

That's nice to know. I didn't find anything on a Global statement used for variables. I'll have to rethink how I have been declaring variables available to all subs and just to subs within a single module.

 

[Evagrius Ponticus]

Thank you Mike! I will stick to Public Variables then . .

 

[mikerickson]

VBEditor help, keyword: Scope has more on this

 

[Colin Legg]

Global is not a VBA reserved word.

Are you sure, Mike?

In a standard module, using this declaration, Global is coloured blue:

[COLOR=blue]Global[/COLOR] str [COLOR=blue]As[/COLOR] [COLOR=blue]String[/COLOR]

And you can't declare a variable called Global:

Dim global as Variant    '<----compile error

So that suggests to me that it is a reserved keyword.


The only difference I'm aware of between Global and Public is that you can't use Global when declaring variables in class modules. I don't ever use Global, although I've seen one or two other people mentioning they do use it.

 

[mikerickson]

Your right, it is reserved.

Entering Global in the Object Browser brings up Load, UnLoad and UserForms.

and when used as in your declaration statement it seems to act like Public.

 

[Evagrius Ponticus]

Yeah - that was the reason I asked - I used both Public and Global and they were treated the same in the code . . .