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I have a question about use of global variables and variables of class using class var.
Declaring variables in class with class var:
unit Unit1;
interface
type
TClass = class
public
class var ObjectList: TObjectList
end;
implementation
end.
Declaring global variables:
unit Unit1;
interface
var
ObjectList: TObjectList
implementation
end.
How does the compiler allocate memory for these two variables?
882
The main difference between Global and local variables is that global variables can be accessed globally in the entire program, whereas local variables can be accessed only within the function or block in which they are defined.
If you want to use that variable even outside the class, you must declared that variable as a global. Then the variable can be accessed using its name inside and outside the class and not using the instance of the class.
Variables that are created outside of a function (as in all of the examples above) are known as global variables. Global variables can be used by everyone, both inside of functions and outside.
These variables are implemented in exactly the same way. The class var is implemented as a global variable. That is there is a single instance of the variable in the module, allocated statically.
The only difference is that the class var is in a different scope, and you can use visibility protection specifiers like private to limit access to the variable.
196
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