Segmentation Fault On Program Termination? - c++

Goran wrote:
> i have a problem on program termination.
>
> At the moment when main() ends my program creates a segmentation
> fault.
>
>
> #include <libmylib/myObject.h>

I suppose you think that whatever is in that header is more or
less irrelevant here, right?

>
> int main() {
>
> using namespace Mylib;
>
> MyObject1_t * aObject1 = 0;
> MyObject2_t aObject2("someString");
>
> aObject1 = new Object1_t(aObject2);

You seem to freely substitue 'MyObject1_t' with 'Object1_t'. Is
that intentional or is it just sloppy posting? If the latter,
please consider what *we* have to work with. We don't have the
rest of your code, we don't have a telepathic link to your brain,
and our crystal ball is having a foggy day today.

>
> delete aObject1; // program still works
>
> // cout or other still works here
>
> return(0); // program creates an seg. fault
>
> }
>
> I know it's maybe tricky to say something to my problem due to missed
> postings of Object1_t and Object2_t but I hope this is some beginner-
> failure

It most likely is, judging by the manner in which the material is
presented.

The usual advice is the following: try reducing your program to the
bare minimum to reproduce the problem. If you can, you might just
be able to figure it out yourself. If not, read the FAQ 5.8 and
follow its recommendations. No, it's not a joke.

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

On Aug 28, 3:53 am, "Victor Bazarov" <v.Abaza...@comAcast.net> wrote:
> Goran wrote:
> > i have a problem on program termination.
>
> > At the moment when main() ends my program creates a segmentation
> > fault.
>
> > #include <libmylib/myObject.h>
>
> I suppose you think that whatever is in that header is more or
> less irrelevant here, right?
>

No, but I hope so...

>
>
> > int main() {
>
> > using namespace Mylib;
>
> > MyObject1_t * aObject1 = 0;
> > MyObject2_t aObject2("someString");
>
> > aObject1 = new Object1_t(aObject2);
>
> You seem to freely substitue 'MyObject1_t' with 'Object1_t'. Is
> that intentional or is it just sloppy posting? If the latter,


Yes, sloopy posting... It should be:

aObject1 = new MyObject1_t(aObject2);

> please consider what *we* have to work with. We don't have the
> rest of your code, we don't have a telepathic link to your brain,
> and our crystal ball is having a foggy day today.
>
>
>
> > delete aObject1; // program still works
>
> > // cout or other still works here
>
> > return(0); // program creates an seg. fault
>
> > }
>
> > I know it's maybe tricky to say something to my problem due to missed
> > postings of Object1_t and Object2_t but I hope this is some beginner-
> > failure
>
> It most likely is, judging by the manner in which the material is
> presented.
>
> The usual advice is the following: try reducing your program to the
> bare minimum to reproduce the problem. If you can, you might just
> be able to figure it out yourself. If not, read the FAQ 5.8 and
> follow its recommendations. No, it's not a joke.
>
> V
> --
> Please remove capital 'A's when replying by e-mail
> I do not respond to top-posted replies, please don't ask

"Goran" <postmaschine> wrote in message
news:1188266356.482183.289160@y42g2000hsy.googlegroups.com...
> On Aug 28, 3:53 am, "Victor Bazarov" <v.Abaza...@comAcast.net> wrote:
>> Goran wrote:
>> > i have a problem on program termination.
>>
>> > At the moment when main() ends my program creates a segmentation
>> > fault.
>>
>> > #include <libmylib/myObject.h>
>>
>> I suppose you think that whatever is in that header is more or
>> less irrelevant here, right?
>>
>
> No, but I hope so...
>
>>
>>
>> > int main() {
>>
>> > using namespace Mylib;
>>
>> > MyObject1_t * aObject1 = 0;
>> > MyObject2_t aObject2("someString");
>>
>> > aObject1 = new Object1_t(aObject2);
>>
>> You seem to freely substitue 'MyObject1_t' with 'Object1_t'. Is
>> that intentional or is it just sloppy posting? If the latter,
>
>
> Yes, sloopy posting... It should be:
>
> aObject1 = new MyObject1_t(aObject2);
>
>> please consider what *we* have to work with. We don't have the
>> rest of your code, we don't have a telepathic link to your brain,
>> and our crystal ball is having a foggy day today.
>>
>>
>>
>> > delete aObject1; // program still works
>>
>> > // cout or other still works here
>>
>> > return(0); // program creates an seg. fault
>>
>> > }
>>
>> > I know it's maybe tricky to say something to my problem due to missed
>> > postings of Object1_t and Object2_t but I hope this is some beginner-
>> > failure
>>
>> It most likely is, judging by the manner in which the material is
>> presented.
>>
>> The usual advice is the following: try reducing your program to the
>> bare minimum to reproduce the problem. If you can, you might just
>> be able to figure it out yourself. If not, read the FAQ 5.8 and
>> follow its recommendations. No, it's not a joke.

Also, a guess, without seeing code, would point to your copy constructor
doing something it shouldn't.

Again, just guessing since you're not showing the code. Another valid guess
would be line 42 of your program.

On 2007-08-28 03:26, Goran wrote:
> Hi all,
>
> i have a problem on program termination.
>
> At the moment when main() ends my program creates a segmentation
> fault.
>
>
> #include <libmylib/myObject.h>
>
> int main() {
>
> using namespace Mylib;
>
> MyObject1_t * aObject1 = 0;
> MyObject2_t aObject2("someString");
>
> aObject1 = new Object1_t(aObject2);
>
> delete aObject1; // program still works
>
> // cout or other still works here
>
> return(0); // program creates an seg. fault
>
> }
>
> I know it's maybe tricky to say something to my problem due to missed
> postings of Object1_t and Object2_t but I hope this is some beginner-
> failure

Can't say anything for sure until you show us the code for MyObject1_t
and MyObject2_t.

My guess would be that they both contains a std::string* (or worse
char*) and that the text used in the constructor for aObject2 is stored
in that. When you create aObject1 with the copy constructor you somehow
fail to properly copy the string and when you later delete aObject1 it
too is deleted. For some reason you then try to dereference the pointer
in the destructor which is why the program crashes.

--
Erik Wikström

Goran wrote:
> Hi all,
>
> i have a problem on program termination.
>
> At the moment when main() ends my program creates a segmentation
> fault.
>
>
> #include <libmylib/myObject.h>
>
> int main() {
>
> using namespace Mylib;
>
> MyObject1_t * aObject1 = 0;
> MyObject2_t aObject2("someString");
>
> aObject1 = new Object1_t(aObject2);
>
> delete aObject1; // program still works
>
> // cout or other still works here
>
> return(0); // program creates an seg. fault
>
> }
>
> I know it's maybe tricky to say something to my problem due to missed
> postings of Object1_t and Object2_t but I hope this is some beginner-
> failure

My guess would be that something in aObject2 gets deleted when you
call
delete aObject1 due to the fact that MyObject1_t stole a pointer from
MyObject2_t during the assignment. When the destructor of MyObject1_t
was called, it deleted its member, whilst the member was never truly
owned.

Read up on "Deep Copying", and "Copy Constructors" in the FAQs.

Regards,

Werner

Goran <postmaschine> wrote in news:1188264416.738284.208330
@y42g2000hsy.googlegroups.com:

> Hi all,
>
> i have a problem on program termination.
>
> At the moment when main() ends my program creates a segmentation
> fault.
>
>
> #include <libmylib/myObject.h>
>
> int main() {
>
> using namespace Mylib;
>
> MyObject1_t * aObject1 = 0;
> MyObject2_t aObject2("someString");
>
> aObject1 = new Object1_t(aObject2);
>
> delete aObject1; // program still works
>
> // cout or other still works here
>
> return(0); // program creates an seg. fault
>
> }
>

See Victor's posting about crystal balls etc, but if I had to guess...

aObject2 is the only variable on the stack and I would guess that it's
destruction at the return is what's causing the fault. Since you pass
in a literal text string, I further guess that aObject2 has grabbed that
pointer and you are trying to delete it when aObject2 is destroyed.

Can't say much more than that with out actual code.

joe

On Aug 28, 1:48 pm, Joe Greer <jgr...@doubletake.com> wrote:
> Goran <postmasch...> wrote in news:1188264416.738284.208330
> @y42g2000hsy.googlegroups.com:
>
>
>
> > Hi all,
>
> > i have a problem on program termination.
>
> > At the moment when main() ends my program creates a segmentation
> > fault.
>
> > #include <libmylib/myObject.h>
>
> > int main() {
>
> > using namespace Mylib;
>
> > MyObject1_t * aObject1 = 0;
> > MyObject2_t aObject2("someString");
>
> > aObject1 = new Object1_t(aObject2);
>
> > delete aObject1; // program still works
>
> > // cout or other still works here
>
> > return(0); // program creates an seg. fault
>
> > }
>
> See Victor's posting about crystal balls etc, but if I had to guess...
>
> aObject2 is the only variable on the stack and I would guess that it's
> destruction at the return is what's causing the fault. Since you pass
> in a literal text string, I further guess that aObject2 has grabbed that
> pointer and you are trying to delete it when aObject2 is destroyed.
>
> Can't say much more than that with out actual code.
>
> joe

Thanks to all! I've found the prob. My object used pointers for member
var. and I had NO copy constructor... Still learning

Goran