473,666 Members | 2,281 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

auto_ptr vs shared_ptr

The main difference between std::auto_ptr and boost::shared_p tr is that
auto_ptr has the transfer-of-ownership semantic. That makes it impossible
to store auto_ptrs in STL containers because the containers use the copy
constructor when you store or get an element.

So, is it recommended to use shared_ptr instead? Are there any
disadvantages of shared_ptr? Is shared_ptr slower maybe?

It seems for shared_ptr you only need the boost headers, not the libraries.
Is that true?

Thanks!
Jul 23 '05 #1
3 7635
Markus Dehmann wrote:

So, is it recommended to use shared_ptr instead? Are there any
disadvantages of shared_ptr? Is shared_ptr slower maybe?

shared_ptr allocates a control block from the heap.
It seems for shared_ptr you only need the boost headers, not the libraries.
Is that true?


Ask on the boost reflector.

--

Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)
Jul 23 '05 #2
Markus Dehmann wrote:
So, is it recommended to use shared_ptr instead? Are there any
disadvantages of shared_ptr? Is shared_ptr slower maybe?


Better don't waste your precious time and join the International Smart
Pointer Haters Club, an ever growing conglomerate of people who think
that smart pointers are not at all a smart idea. See e.g.
http://groups-beta.google.com/group/...6742e2b0036832

Jul 23 '05 #3


Markus Dehmann schreef:
The main difference between std::auto_ptr and boost::shared_p tr is that
auto_ptr has the transfer-of-ownership semantic. That makes it impossible
to store auto_ptrs in STL containers because the containers use the copy
constructor when you store or get an element.

So, is it recommended to use shared_ptr instead? Are there any
disadvantages of shared_ptr? Is shared_ptr slower maybe?
Disadvantages? Sure, the share count had to be stored somewhere.
sizeof(auto_ptr <T>)==sizeof(T* ) on many systems. Furthermore, this
may decrease the cache efficiency.

Furthermore, if the semantics you need /are/ transfer of ownership
(source/sink functions) then std::auto_ptr makes it clear what happens.

It seems for shared_ptr you only need the boost headers, not the libraries.
Is that true?


AFAIK, yes, but that's technically off-topic (and it could change).

Regards,
Michiel Salters

Jul 23 '05 #4

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

Similar topics

3
17128
by: SerGioGio | last post by:
Hello ! When a ref. counted smart pointer (template) class is available (like boost::shared_ptr), is there any (semantic) reason to still use std::auto_ptr rather than this smart pointer ? Or should one use shared_ptr for every cases ? Thanks in advance for your remarks ! SerGioGio
5
2909
by: ctick | last post by:
Are there any advantages of using boost::shared_ptr other than auto_ptr from standard library?
2
2345
by: stephen henry | last post by:
Hi all, I'm trying to create a vector of pointers to a class: For example: class CMb ... std::vector< CMb* > myvect(100);
9
2246
by: BekTek | last post by:
How do you think? and why?
3
3500
by: Evgeny | last post by:
Hi, all! I didn't find yet solution for this problem! Somebody knows where is a catch? Looks like "operator =" or copy constructor not implemented in one of internal templates.... Thanks in advance class CMyBase;
10
4485
by: red floyd | last post by:
It seems that the use of auto_ptr<> is discouraged in many places in favor of boost::shared_ptr<> (or tr1::shared_ptr<>). But consider a PIMPL idiom, where there is a strict 1-1 relationship between interface objects and implementation object, and the implementation object lasts for the lifetime of the interface object. i.e. // header file class WidgetImpl; class Widget {
4
1285
by: Doug Haber | last post by:
Hi All, Everyone tells me that auto_ptr is a good idea, but auto_ptr and COM don't play nice. Can someone please explain why auto_ptr and COM don't like each other and what a reasonable/typical solution is? My guess is that auto_ptr will call the destructor on the COM object which is bad because it should call Release(). I'd like to avoid manually calling Release(), because my function has a bunch of places from which it can return,...
18
2837
by: Dilip | last post by:
I can't believe I am unable to get this simple thing right. I have an auto_ptr class to a structure type. I have it as a member variable in my class. struct Y { SomeType& m_st; Y(SomeType& st) : m_st(st) { } };
39
864
by: Andre Siqueira | last post by:
Hello all, I have a member function like thist: Query(const std::string & id, std::auto_ptr<Modifiermodif = std::auto_ptr<Modifier>()) when a try to instantiate a Query like Query("123");
0
8443
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
8356
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
8866
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
8550
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,...
1
6192
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
4366
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
2769
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
2
2011
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.
2
1772
bsmnconsultancy
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...

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.