Global variable list (GVL):
{attribute 'qualified_only'}
VAR_GLOBAL
nVar : INT;
END_VAR
Within a POU, for example MAIN, the global variable nVar can only be addressed using the prefix GVL:
GVL.nVar := 5;
The following incomplete call of the variables would generate an error:
nVar := 5;
remove the attribute if you just want to use nVar for the available.