From: "Rego, P." <pvrego@gmail.com>
Cc: mailbox@dmitry-kazakov.de
Subject: Re: Constructors with multiple inheritance
Date: Tue, 8 Nov 2011 18:24:53 -0800 (PST)
Date: 2011-11-08T18:24:53-08:00 [thread overview]
Message-ID: <21605158.153.1320805494018.JavaMail.geo-discussion-forums@yqiu15> (raw)
In-Reply-To: <1gnrks1djlaok.1k0r5f8z9ylfx.dlg@40tude.net>
> function Construct (Object_Reference : access Parent_Class)
> return Parent_Class_Ptr;
I tried this approach in the following code, but it still complains about the null object.
-- test_pkg.ads
package Test_Pkg is
type Test_Class is tagged;
type Test_Class_Ptr is access all Test_Class;
function Construct (T : access Test_Class) return Test_Class_Ptr;
task type Primary_Task (This : not null access Test_Class);
type Test_Class is tagged limited
record
Info : Integer := 0;
Value : Float;
Primary : Primary_Task (Test_Class'Access);
end record;
end Test_Pkg;
-- test_pkg.adb
with Text_IO; use Text_IO;
package body Test_Pkg is
task body Primary_Task is
begin
loop
Put_Line (Integer'Image (This.Info) & "__");
delay 0.2;
end loop;
end Primary_Task;
function Construct (T : access Test_Class) return Test_Class_Ptr is
T_Ptr : constant Test_Class_Ptr := new Test_Class;
begin
T_Ptr.Info := T.Info + 1;
T_Ptr.Value := 0.0;
return T_Ptr;
end Construct;
end Test_Pkg;
-- test_pkg_user.adb
with Test_Pkg;
with Text_IO; use Text_IO;
procedure Test_Pkg_User is
Test_Obj : Test_Pkg.Test_Class_Ptr;
begin
Test_Obj := Test_Obj.Construct;
Put_Line ("Value = "&Integer'Image (Test_Obj.Info));
end Test_Pkg_User;
The message I get is the following:
c:\tst>gnatmake test_pkg_user.adb
gcc -c test_pkg_rev623_user.adb
test_pkg_user.adb:12:16: warning: null value not allowed here
test_pkg_user.adb:12:16: warning: "Constraint_Error" will be raised at run time
gcc -c test_pkg.adb
gnatbind -x test_pkg_user.ali
gnatlink test_pkg_user.ali
What am I still doing wrong? Thanks again.
Note: Sure if I put in test_pkg_user.adb
Test_Obj : Test_Pkg.Test_Class_Ptr := new Test_Pkg.Test_Class;
it returns me a build with no warning, but I think this way I allocate memory twice to the pointer (one in the call new Test_Pkg.Test_Class and the other in the construct method execution), right?
next prev parent reply other threads:[~2011-11-09 2:25 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-29 19:40 Constructors with multiple inheritance Rego, P.
2011-09-29 20:20 ` Dmitry A. Kazakov
2011-09-30 3:11 ` Rego, P.
2011-09-30 7:36 ` Dmitry A. Kazakov
2011-09-30 14:04 ` Rego, P.
2011-09-30 16:29 ` Robert A Duff
2011-09-30 19:14 ` Rego, P.
2011-09-30 16:42 ` Dmitry A. Kazakov
2011-09-30 19:42 ` Rego, P.
2011-10-06 12:46 ` Julian Leyh
2011-11-09 2:24 ` Rego, P. [this message]
2011-11-09 8:39 ` Dmitry A. Kazakov
2011-11-10 3:47 ` Rego, P.
2011-11-10 7:09 ` AdaMagica
2011-11-10 7:20 ` AdaMagica
2011-11-10 8:35 ` Dmitry A. Kazakov
2011-11-12 15:16 ` Rego, P.
2011-11-12 15:30 ` Rego, P.
2011-11-12 16:28 ` Dmitry A. Kazakov
2011-11-12 17:41 ` Rego, P.
2011-11-10 8:33 ` Simon Wright
2011-11-10 9:01 ` Georg Bauhaus
2011-11-10 9:09 ` Georg Bauhaus
2011-11-10 18:16 ` Jeffrey Carter
2011-11-10 19:39 ` Dmitry A. Kazakov
2011-11-09 9:00 ` Simon Wright
2011-11-10 3:54 ` Rego, P.
2011-10-07 0:08 ` Shark8
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