473,569 Members | 2,880 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

private copy ctor for exception handling class

Consider the following program:

#include <cstdlib>
#include <iostream>

using namespace std;

class Test
{
public:
Test();
inline int value() const;

private:
Test(const Test &rhs);
int x;
};

Test::Test()
{
cout << "From Test default ctor" << endl;
x = 100;
}

inline int Test::value() const
{
return x;
}

Test::Test(cons t Test &rhs)
{
cout << "From Test copy ctor" << endl;
}

void fn1()
{
Test obj;
throw obj;
}

int main()
{
try
{
fn1();
}
catch (const Test &e)
{
cout << "Exception caught. Value = " << e.value() <<
endl;
}

return EXIT_SUCCESS;
}

When I compile this program x.cpp as

g++ -std=c++98 -pedantic -Wall -Wextra x.cpp

I get the following compilation error.

x.cpp: In function `void fn1()':
x.cpp:29: error: `Test::Test(con st Test&)' is private
x.cpp:36: error: within this context

In the catch clause in 'main()', I am receiving Test object only as
reference. So no copying of object is involved. But still the compiler
gives copy ctor being private. Why is the copy ctor needed here ?

Even if I write fn1() as,

void fn1()
{
throw Test();
}

I get the same error.

Kindly clarify.

Thanks
V.Subramanian
Jul 17 '08 #1
0 1004

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

Similar topics

1
1854
by: Rich | last post by:
Hi, I have a query regarding VC6 and its handling of templated copy constructors. Here goes: Take a look at the following code sample... template<class _Ty, size_t t_uiSize = 10 > class my_template
5
3020
by: PasalicZaharije | last post by:
Hallo, few days ago I see ctor like this: Ctor() try : v1(0) { // some code } catch(...) { // some code }
5
1686
by: nagrik | last post by:
Hello group, Last week I picked up a thread, which pointed out that if a copy constructor is created with pointers instead of reference, there is a danger of it going in infinite recursion. My observation: 1. Compiler does not complain.
8
2728
by: Grizlyk | last post by:
Good morning. Look here: http://groups.google.com/group/fido7.ru.cpp.chainik/browse_frm/thread/7341aba5238c0f79 and here: http://groups.google.com/group/fido7.ru.cpp.chainik/browse_frm/thread/cb014f4ba9df614a Can anybody answer? Who can't read in russian:
3
3381
by: John Salmon | last post by:
g++ complains about illegal access to a private member when the following is compiled with a private copy constructor for the class C. When the copy constructor is public, the program runs and demonstrates(?) that the copy constructor is never called (at least no sign of its chatter on std::cout is visible). So - is it necessary to have a...
10
3995
by: campos | last post by:
"Effective C++ 3rd Edition" Item 6, P39 ------------------------------------------------------- class Uncopyable { protected: // allow construction Uncopyable() {} // and destruction of ~Uncopyable() {} // derived objects... private: Uncopyable(const Uncopyable&); // ...but prevent copying
13
2448
by: Jeroen | last post by:
Hi all, I'm trying to implement a certain class but I have problems regarding the copy ctor. I'll try to explain this as good as possible and show what I tried thusfar. Because it's not about a certain code syntax but more a 'code architecture' thing , I'll use simple example classes (which are certainly not complete or working...) just to...
4
2708
by: Johs | last post by:
I have this in a file called bas.h: #ifndef BAS_H_ #define BAS_H_ class GeoObj { public: void draw() const; int getNum();
2
2153
by: subramanian100in | last post by:
If we do not provide any ctor for a class, the compiler provides the default ctor and copy ctor if needed. Consider a class Test. Suppose we provide some ctor in class Test but do not provide the default ctor. Suppose we try to create Test obj;
0
7703
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...
0
7619
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...
0
7930
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. ...
0
6290
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...
1
5514
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...
0
5228
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...
0
3651
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
2118
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
0
950
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...

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.