PLSQL: Changing in parameter thru assignment to global variable???

Question

Hi there!
On 10gR2 (10.2.0.3) the following PL/SQL block
declare
glob_val pls_integer := 2;
procedure test_p(x in pls_integer) is
begin
dbms_output.put_line(x);
glob_val := 3;
dbms_output.put_line(x);
end test_p;
begin
dbms_output.enable;
test_p((glob_val));
end;
appears to change the value of the in-parameter x by an assignment to the
global variable glob_val. To verify, just check the dbms_output generated.
This is completely unexpected behaviour, and contrary to my understanding of
PL/SQL's parameter passing mechanisms. If this was the intended behaviour
in 10.2 it would definitely break tons of existing PL/SQL code.
Has anyone run into this problem before? Is this a bug? Is there a workaround
available? Any ideas??
All the best
Michael

Answer 1

Sorry, I cannot accept that statement.
According to the PL/SQL user's guide
<QUOTE>
Using the IN Mode
An IN parameter lets you pass values to the subprogram being called. Inside the subprogram, an IN parameter acts like a constant. It cannot be assigned a value.
You can pass a constant, literal, initialized variable, or expression as an IN parameter.
IN parameters can be initialized to default values, which are used if those parameters are omitted from the subprogram call. For more information, see "Using Default Values for Subprogram Parameters".
</QUOTE>
IN-Parameter were not passed by reference in former versions of PL/SQL.
You may notice that you cannot assign to an in-parameter either; an attempt
to do that will just produce the error PLS-00363.