473,797 Members | 3,079 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Destructors

Hi

when do you use destructors and what are the advantages /disadvantages?

ch Jim
Nov 17 '05 #1
3 2100

"Jimmy" <be****@gmail.c om> wrote in message
news:Ob******** ******@TK2MSFTN GP15.phx.gbl...
Hi

when do you use destructors and what are the advantages /disadvantages?

ch Jim


Use destructors anytime you need to cleanup when the class gets destroyed.
Basically, you would implement the IDisposable interface's Dispose() method.
Normally, cleanup includes closing any open files, closing database
connections, cleaning up unmanaged resources, et cetera.

HTH,
Mythran

Nov 17 '05 #2
but what are the disadvantages if any?

ch Jim
"Mythran" <ki********@hot mail.comREMOVET RAIL> wrote in message
news:Ou******** ******@TK2MSFTN GP15.phx.gbl...

"Jimmy" <be****@gmail.c om> wrote in message
news:Ob******** ******@TK2MSFTN GP15.phx.gbl...
Hi

when do you use destructors and what are the advantages /disadvantages?

ch Jim
Use destructors anytime you need to cleanup when the class gets destroyed.
Basically, you would implement the IDisposable interface's Dispose()

method. Normally, cleanup includes closing any open files, closing database
connections, cleaning up unmanaged resources, et cetera.

HTH,
Mythran

Nov 17 '05 #3
Dispose is not a destructor.

A disadvantage of using a Destructor is that it does not allow for explicit clean-up of an object at runtime. The Dispose method is
a way of saying, "Hey, clean me up before you go!" to consuming classes. This allows for the explicit and timely release of
unmanaged resources such as Database connections and File references, etc. when the consuming classes no longer require the object
reference.

Once "Disposed", an object should be rendered unusable but it's up to the designer to explicitly throw an ObjectDisposedE xception
when members are accessed on a disposed custom class. You don't see this done too often :)

If you inherit from System.Componen tModel.Componen t, you receive a base implementation that prevents the GC (Garbage Collector) from
destroying your object without calling the virtual Dispose method first. This way, all of your cleanup code can be located in one
place. Neat.

I'm sure there are more disadvantages, but I can't think right now -- it's late.

--
Dave Sexton
dave@www..jwaon line..com
-----------------------------------------------------------------------
"Jimmy" <be****@gmail.c om> wrote in message news:eZ******** ******@TK2MSFTN GP15.phx.gbl...
but what are the disadvantages if any?

ch Jim
"Mythran" <ki********@hot mail.comREMOVET RAIL> wrote in message
news:Ou******** ******@TK2MSFTN GP15.phx.gbl...

"Jimmy" <be****@gmail.c om> wrote in message
news:Ob******** ******@TK2MSFTN GP15.phx.gbl...
> Hi
>
> when do you use destructors and what are the advantages /disadvantages?
>
> ch Jim
>
>


Use destructors anytime you need to cleanup when the class gets destroyed.
Basically, you would implement the IDisposable interface's Dispose()

method.
Normally, cleanup includes closing any open files, closing database
connections, cleaning up unmanaged resources, et cetera.

HTH,
Mythran


Nov 17 '05 #4

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

3
21394
by: Rajesh Garg | last post by:
Can we have private constructors and destructors? IF yes what is the use of such constructors or destructors.....in the sense where can these be implemented in a system................. I have an idea that we can have private constructors and destructors but am not able to find a situation where they can be used... Regards RVG rajeshgarg@opussoft.com
3
2720
by: Nuno Barros | last post by:
Cn someone tell me if when i call the destructor of a derivated class, the destructor of the base class is called implicitly? Or shall i call the destructor by myself? Thanks in advance Nuno Barros
12
1819
by: Ross Boylan | last post by:
I am trying to understand under what circumstances destructors get called with std::vector. I have an application in which I will put real objects, not just pointers, in the vector. 1. The standard says that empty() has constant complexity. If it actually called the destructor for each object, it seems to me it would have linear complexity. Does empty() call the destructor for each object in the container? If yes, why is it described...
8
1430
by: johny smith | last post by:
If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? thanks!
7
1891
by: qazmlp | last post by:
When a member function is declared as virtual in the base class, the derived class versions of it are always treated as virtual. I am just wondering, why the same concept was not used for the destructors. What I am expecting is, if the destructor is declared as virtual in base, the destructors of all its derived classes also should be virtual always. What exactly is the reason for not having it so?
26
2729
by: Michi Henning | last post by:
I've been having problem with destructors in the context of having ported C# code developed under .NET to Mono. What happens is that, on a dual-CPU machine, various parts of the code crash randomly (and rarely). This always happens during process shutdown, after some thread has called System.Environment.Exit(). Clearly, some sort of race condition. Note that what follows only applies to destructors that are called when the process shuts...
8
1807
by: Edward Diener | last post by:
I have a __value class which uses some legacy C++ code. So I wrapped the legacy C++ code in another __nogc class and have a pointer to that class as a member of my __value class. When the __value class is created, I dynamically allocate an object of the class with the legacy C++ code. However because the __value class has no destructor, I can never release that allocated memory. Why does a __value class allow no destructor ? Without it I...
3
1898
by: alex.gman | last post by:
If I have code like this int f() { // ... stuff ... g(); if(x > 0) return (x+4); // ... more stuff ... always_call(z); return y; }
6
7533
by: mlw | last post by:
Could someone explain why there is no destructor in Java classes? There are many times you need to be called WHEN an object goes out of scope and not when it will eventally be freed.
6
5168
by: Jeff Newman | last post by:
Hello, Could anyone explain to me why the following class's destructor shows up as having multiple branches? (At least as judged by gcov 4.1.2 when compiled with gcc 4.1.2 ): struct blah { blah(); virtual ~blah();
0
9536
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
10468
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
1
10205
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
10021
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
9063
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
1
7559
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
6802
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5458
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
5582
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.