Construction and destruction of objects when exceptions are thrown

[thamizh.veriyan]

I compiled this code on gcc 4.1.2 and the output I got seems to be a
bit weird.

Here is the code:

#include <iostream>

class A{
public:
A(){std::cout << "Constructor" << std::endl;}
~A(){std::cout << "Destructor" << std::endl;}
};

void display(){
A mystr;
throw mystr;
}

int main() {
try{
display();
}
catch(A str){
}
return 0;
}

The output happens to be:
Constructor
Destructor
Destructor
Destructor

I don't know if I am missing something. I checked all the references
that I have for exceptions. Looks like local objects get deleted
normally when exceptions are thrown. I cant seem to explain this
output. Would be grateful if the members here can help me with this.

Regards
Dana

[Victor Bazarov]

th*************@gmail.com wrote:

I compiled this code on gcc 4.1.2 and the output I got seems to be a
bit weird.

Here is the code:

#include <iostream>

class A{
public:
A(){std::cout << "Constructor" << std::endl;}
~A(){std::cout << "Destructor" << std::endl;}
};

void display(){
A mystr;
throw mystr;
}

int main() {
try{
display();
}
catch(A str){
}
return 0;
}

The output happens to be:
Constructor
Destructor
Destructor
Destructor

I don't know if I am missing something. I checked all the references
that I have for exceptions. Looks like local objects get deleted
normally when exceptions are thrown. I cant seem to explain this
output. Would be grateful if the members here can help me with this.

Your 'A' class has a copy constructor which you forgot to consider.

V
--
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[John Harrison]

>>

>>I don't know if I am missing something. I checked all the references
that I have for exceptions. Looks like local objects get deleted
normally when exceptions are thrown. I cant seem to explain this
output. Would be grateful if the members here can help me with this.

Your 'A' class has a copy constructor which you forgot to consider.

V

It's just incredible how many times we get this post.

john

[Piyo]

th*************@gmail.com wrote:

>
int main() {
try{
display();
}
catch(A str){

catch(A &str){ <-- catch using refs
On a related note, please make it a habit to catch by reference. It's
highly recommended (not required).

http://www.parashift.com/c++-faq-lit....html#faq-17.7

}
return 0;
}

[Victor Bazarov]

John Harrison wrote:

>>I don't know if I am missing something. I checked all the references
that I have for exceptions. Looks like local objects get deleted
normally when exceptions are thrown. I cant seem to explain this
output. Would be grateful if the members here can help me with this.

Your 'A' class has a copy constructor which you forgot to consider.

V

It's just incredible how many times we get this post.

If it's so frequently asked (which I can't vouch for), then perhaps
somebody <wink-winkcould write up an entry for Marshall Cline to
add to the FAQ Lite...

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask