Copy constructor, why in return by value functions

Posted by fsdfa on Stack Overflow See other posts from Stack Overflow or by fsdfa
Published on 2010-04-25T07:48:17Z Indexed on 2010/04/25 7:53 UTC
Read the original article Hit count: 231

Filed under:

const

|

copy

|

constructor

|

c++

Suppose i have: http://pastebin.com/FSnzYFFx

Then I'll get a compile error in the last line. But if I add 'const' before 'A&', its ok.

I want to know why. Where it's exactly the problem? I dont get why it should be const.

Language: C++

© Stack Overflow or respective owner

Related posts about const

what is the difference between const int*, const int * const, int const *

as seen on Stack Overflow - Search for 'Stack Overflow'
I always mess up how to use it correctly. Is there a set of rules defining what you can and cannot do? I want to know all the Do's and all DoNOTs in terms of assignments, passing to the functions, etc. Thanks >>> More
Modifying a const through a non-const pointer

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm a bit confused what happened in the following code: const int e = 2; int* w = ( int* ) &e; // (1) cast to remove const-ness *w = 5; // (2) cout << *w << endl; // (3) outputs 5 cout << e << endl; // (4) outputs 2 cout… >>> More
What is the best Broadphase Interface for moving spheres?

as seen on Game Development - Search for 'Game Development'
As of now I am working on optimizing the performance of the physics and collision, and as of now I am having some slowdowns on my other computers from my main. I have well over 3000 btSphereShape Rigidbodies and 2/3 of them do not move at all, but I am noticing(by the profile below) that collision… >>> More
Template inheritence c++

as seen on Stack Overflow - Search for 'Stack Overflow'
I have made a template singleton class, I have also made a data structure that is templated. My question is; how do I make my templated data structure inherit from a singleton so you can only have one float type of this structure? I have tested both seperate and have found no problems. Code provided… >>> More
Higher order function « filter » in C++

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi all. I wanted to write a higher order function filter with C++. The code I have come up with so far is as follows: #include <iostream> #include <string> #include <functional> #include <algorithm> #include <vector> #include <list> #include <iterator> using… >>> More

Related posts about copy

encfs error while decoding the data

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have installed encfs and started using it to secure all my personal & office data and it was working absolutely fine until 2 hours back. The setup is like this. I have a folder in Copy folder called OfficeData which gets synchronized with my Copy folder When I login into the system I use… >>> More
XSL How to copy identical + add copy with attributes changes

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello I need to copy a node and its sub-nodes: first: one identical copy followed by a modified copy with some attributes values changed Here is the extract to change: <Configuration Name="Debug|Win32" OutputDirectory=".\Debug" IntermediateDirectory=".\Debug" ATLMinimizesCRunTimeLibraryUsage="FALSE" … >>> More
Problems with wireless file copy - hangs during copy

as seen on Super User - Search for 'Super User'
I have this problem on my home network where when I try to copy files via wireless connection, at some point the copy fails and the machine doing the copy loses connection to the network. I'm pretty much lost as to figuring out the source for the problem... Some more details that might help: It's… >>> More
Copy files in Linux, avoid the copy if files do exist in destination

as seen on Super User - Search for 'Super User'
Hi, I need to copy a /home/user folder from one hardisk to another one. It has 100000 files and around 10G size. I use cp -r /origin /destination sometines I get some errors due to broken links, permissions and so on. So I fix the error, and need to start again the copy. I wonder how could… >>> More
AMD 24 core server memory bandwidth

as seen on Server Fault - Search for 'Server Fault'
I need some help to determine whether the memory bandwidth I'm seeing under Linux on my server is normal or not. Here's the server spec: HP ProLiant DL165 G7 2x AMD Opteron 6164 HE 12-Core 40 GB RAM (10 x 4GB DDR1333) Debian 6.0 Using mbw on this server I get the following numbers: foo1:~# mbw… >>> More