Package body variable- is it always safe to use it?

Question

In a package spec i have a function "function1" and in package body this functions does following:
1) it evaluate/calculate a variable/value "Flag1".
2) it calls 4 (package body) functions that needs to use value "Flag1".
I have forgotten how "package body variables" work. Is it safe to declare variable "Flag1" in a "package body" level? So that "function1" can initialize this variable and 4 functions can use this variable later too. Or it is not safe if i have lot of sessions in my database which may go into conflict with sharing this "flag1"? And i perhaps better send "flag1" as function parameter to all 4 functions?

Answer 1

Easy enough to test, but it depends on what you mean by the "next run".
In the same session:
SQL > CREATE PACKAGE p AS
  2     FUNCTION f1(p_v1 IN NUMBER) RETURN NUMBER;
  3  END;
  4  /
Package created.
SQL > CREATE PACKAGE BODY p AS
  2     g_var VARCHAR2(10);
  3
  4  FUNCTION f2(p_v2 IN VARCHAR2) RETURN NUMBER IS
  5  BEGIN
  6     DBMS_OUTPUT.Put_Line('Value of g_var in f2 is: '||g_var);
  7     RETURN 1;
  8  END;
  9
10  FUNCTION f1 (p_v1 IN NUMBER) RETURN NUMBER IS
11     l_res NUMBER;
12  BEGIN
13     DBMS_OUTPUT.Put_Line('Value of g_var at start f1 is: '||g_var);
14     SELECT dummy INTO g_var FROM dual;
15     l_res := f2(g_var);
16     g_var := 'A';
17     DBMS_OUTPUT.Put_Line('Value of g_var at end f1 is: '||g_var);
18     RETURN l_res;
19  END;
20  END;
21  /
Package body created.
SQL > var v number;
SQL > exec :v := p.f1(1);
Value of g_var at start f1 is:
Value of g_var in f2 is: X
Value of g_var at end f1 is: A
PL/SQL procedure successfully completed.
SQL > exec :v := p.f1(2);
Value of g_var at start f1 is: A
Value of g_var in f2 is: X
Value of g_var at end f1 is: A
PL/SQL procedure successfully completed.but after running it in one session, then doing the "next run" in a different session:
SQL > exec :v2 := p.f1(1);
Value of g_var at start f1 is:
Value of g_var in f2 is: X
Value of g_var at end f1 is: A
PL/SQL procedure successfully completed.John