Pseudo destructor

Steven T. Hatton

ISO/IEC 14882:2003:

"5.2.4 Pseudo destructor call [expr.pseudo]

The use of a pseudo-destructor-name after a dot . or arrow -> operator
represents the destructor for the non-class type named by
type-name. The result shall only be used as the operand for the
function call operator (), and the result of such a call has type
void. The only effect is the evaluation of the postfix- expression
before the dot or arrow.

The left hand side of the dot operator shall be of scalar type. The
left hand side of the arrow operator shall be of pointer to scalar
type. This scalar type is the object type. The type designated by the
pseudo-destructor-name shall be the same as the object type.
Furthermore, the two type-names in a pseudo-destructor-name of the
form

::opt nested-name-specifieropt type-name :: ~ type-name

shall designate the same scalar type. The cv-unqualified versions of
the object type and of the type desig- nated by the
pseudo-destructor-name shall be the same type."
Hu?????
--
STH
Hatton's Law: "There is only One inviolable Law"
KDevelop: http://www.kdevelop.org SuSE: http://www.suse.com
Mozilla: http://www.mozilla.org

Jul 22 '05 #1

Subscribe Reply

3314

Ron Natalie

"Steven T. Hatton" <su******@setid ava.kushan.aa> wrote in message news:pvydnSp6hq j5bIPcRVn->

Hu?????
--

You don't elaborate on what you don't understand. But let me expound on the passage
you quoted.

Class types all have either explicit or implicit "REAL" destructors '(if you don't define
a destructor one will be defined for you). Other types, like ints for example, don't
really have destructor. However, primarily for the benefit of templates, you're allowed
to make what appears to be a destructor call to them.

Some of the templated containers, such as vectors, make use of this. They will destruct
and element to get "rid" of the instance without freeing the memory and then placement
construct a new one on top of the existing memory. Without the psuedo destructor,
they'd have to specialize the template for non class types to get rid of the destructor
calls.

Jul 22 '05 #2

Similar topics

26994

C++: destructor and delete

by: Newsnet Customer | last post by:

Hi, Statement 1: "A dynamically created local object will call it's destructor method when it goes out of scope when a procedure returms" Agree. Statement 2: "A dynamically created object will call it's destructor when it is made a target of a delete".

C / C++

10506

Virtual Destructor

by: Stub | last post by:

Please answer my questions below - thanks! 1. Why "Derived constructor" is called but "Derived destructor" not in Case 1 since object B is new'ed from Derived class? 2. Why "Derived destructor" is called in Case 2 since only ~base() becomes "virtual" and ~Derived() is still non-virtual? 3. Does Case 3 show that we don't need any virtual destructor to make ~Derived() called? 4. Is "virtual destructor" needed only for Case 2?

C / C++

6224

RFC: clc-compliant pseudo-random number generator

by: Ben Pfaff | last post by:

One issue that comes up fairly often around here is the poor quality of the pseudo-random number generators supplied with many C implementations. As a result, we have to recommend things like using the high-order bits returned by rand() instead of the low-order bits, avoiding using rand() for anything that wants decently random numbers, not using rand() if you want more than approx. UINT_MAX total different sequences, and so on. So I...

C / C++

5284

Dispose / Destructor Guidance (long)

by: Ken Durden | last post by:

I am in search of a comprehensive methodology of using these two object cleanup approaches to get rid of a number of bugs, unpleasantries, and cleanup-ordering issues we currently have in our 4-month old C#/MC++ .NET project project. I'd like to thank in advance anyone who takes the time to read and/or respond to this message. At a couple points, it may seem like a rant against C# / .NET, but we are pretty firmly stuck with this approach...

C# / C Sharp

3306

Destructor: not gauranteed to be called?

by: Peter Oliphant | last post by:

I'm programming in VS C++.NET 2005 using cli:/pure syntax. In my code I have a class derived from Form that creates an instance of one of my custom classes via gcnew and stores the pointer in a member. However, I set a breakpoint at the destructor of this instance's class and it was never called!!! I can see how it might not get called at a deterministic time. But NEVER? So, I guess I need to know the rules about destructors. I would...

.NET Framework

1978

Missing Destructor

by: AB | last post by:

Hi All, I've got an array of objects, during the execution of the program I'd like to assign a particular object to a certain element in the object array. The sample code's like this... class ClassA { public: ClassA()

C / C++

2583

private destructor and templates

by: Ben Voigt | last post by:

I have a POD type with a private destructor. There are a whole hierarchy of derived POD types, all meant to be freed using a public member function Destroy in the base class. I get warning C4624. I read the description, decided that it's exactly what I want, and ignored the warning. Now I'm trying to inherit using a template. Instead of "destructor could not be generated because a base class destructor is inaccessible", I now have an...

.NET Framework

2043

The "stealing code from the destructor" bug

by: gw7rib | last post by:

I've been bitten twice now by the same bug, and so I thought I would draw it to people's attention to try to save others the problems I've had. The bug arises when you copy code from a destructor to use elsewhere. For example, suppose you have a class Note. This class stores some text, as a linked list of lines of text. The destructor runs as follows: Note::~Note() {

C / C++

1993

About virtual destructor

by: sam | last post by:

Hi, See when i reading a sourcecode of a program, I read that the constructor is ordinary and after that the programmer has written virtual destructor for that constructor . Why we use the virtual destructor whats the use of it? the code is like this: Network(int input,int output); Network(&Network); virtual ~Network();

C / C++

8153

Changing the language in Windows 10

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,...

Windows Server

8653

Problem With Comparison Operator <=> in G++

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...

C / C++

8595

Maximizing Business Potential: The Nexus of Website Design and Digital Marketing

by: jinu1996 | last post by:

In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...

Online Marketing

8455

Discussion: How does Zigbee compare with other wireless protocols in smart home applications?

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...

General

7126

AI Job Threat for Devs

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...

Career Advice

6101

Access Europe - Using VBA to create a class based on a table - Wed 1 May

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...

Microsoft Access / VBA

2587

transfer the data from one system to another through ip address

by: 6302768590 | last post by:

Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

C# / C Sharp

1760

How to add payments to a PHP MySQL app.

by: muto222 | last post by:

How can i add a mobile payment intergratation into php mysql website.

PHP

1459

Comprehensive Guide to Website Development in Toronto: Expert Insights from BSMN Consultancy

by: bsmnconsultancy | last post by:

In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

General