Unless the %assume-local parse directive is used, variables not in a parameter list automatically have global scope unless the first reference is prefixed with my. Variable names in a parameter list are always local to their associated function, method, or catch block. Global variables can be explicitly declared with our. The our keyword is required if the parse option %require-our (-O or --require-our command-line option) is set for the parent program. See the section on Parse Options for more information.

When the %assume-local parse directive is used, variables without an explicit scope declaration (i.e. my or our) are assumed to be local variables.

Variables may be assigned any value unless restricted with a type declaration. If no type declaration is given, then the variable is assumed to be type any. Note that type declarations are required for all variables (and for function and method parameters and class members) when the %require-types parse option is set.

Local variables are not shared between threads (local variables have a distinct value in each thread), however global variables are. See Threading (and in particular Threading and Variables) for more information.

For example (in the following script, the our keyword is optional):

#!/usr/bin/qore
#
# variable scoping example

our int $a = 1;                    # this is a global variable
our (string $b, any $c, hash $d);  # list of global variables

if ($a == 1) {
    my int $a = 2; 
    my (string $b, any $c);
    # $a, $b, and $c are local variables, 
    # the use of which will not affect the 
    # global variables of the same name
    print("local a = %d\n", $a); 
}

print("global a = %d\n", $a); 

The first print() statement will output:

local a = 2

The second print() statement will output:

global a = 1