Global variables
From Free Pascal wiki
Jump to navigationJump to searchA global variable is one that is defined in the main program of a program or the main part of a unit. Globals declared in a program cannot be accessed from a unit, but globals in a unit can be accessed from a main program or a unit that accesses that unit.
var i:integer;
begin end.
i is a global variable.
External variable
External variable is a global variable has been declared in unit interface section.