• Tony (5/5) Nov 12 2017 I am getting the message from my program execution:
• codephantom (11/16) Nov 12 2017 More info than that is needed.
• Tony (3/21) Nov 12 2017 I am on Ubuntu 16.04. Thanks, I didn't know that "producing a
• =?UTF-8?Q?Ali_=c3=87ehreli?= (8/11) Nov 12 2017 It is. If you search for "where is core file ubuntu" you will hit the
• Tony (3/15) Nov 13 2017 My mistake. When I said "and it isn't", I was trying to say "and
• Tony (2/7) Nov 13 2017 Thanks for the "man core" tip and the link.
• codephantom (17/19) Nov 13 2017 ok. that's because Ubuntu is not (by default) setup for
• Antonio Corbi (13/32) Nov 13 2017 Hi,

Tony <tonytdominguez aol.com> writes:

I am getting the message from my program execution:

"Segmentation fault (core dumped)"

But I don't see a core file in the current directory or in my 
home directory. Is there one somewhere? Would I be able to do 
anything meaningful with it if it exists?

codephantom <me noyb.com> writes:

On Monday, 13 November 2017 at 05:01:18 UTC, Tony wrote:
 I am getting the message from my program execution:

 "Segmentation fault (core dumped)"

 But I don't see a core file in the current directory or in my 
 home directory. Is there one somewhere? Would I be able to do 
 anything meaningful with it if it exists?

More info than that is needed.

What platform are you on?

Do you have core dumps enabled/disabled?

If you have it enabled...where does it put them?

And yes, core dumps are potentially useful for debugging.

However, given you're asking that question, and getting core 
dumps, then it might be easier for you to use the -g option when 
you compile, and then run your executable (or a.out) through a 
debugger:

https://www.youtube.com/watch?v=vcVmWbYEIsk

Tony <tonytdominguez aol.com> writes:

On Monday, 13 November 2017 at 05:37:12 UTC, codephantom wrote:
 On Monday, 13 November 2017 at 05:01:18 UTC, Tony wrote:
 I am getting the message from my program execution:

 "Segmentation fault (core dumped)"

 But I don't see a core file in the current directory or in my 
 home directory. Is there one somewhere? Would I be able to do 
 anything meaningful with it if it exists?

 More info than that is needed.

 What platform are you on?

 Do you have core dumps enabled/disabled?

 If you have it enabled...where does it put them?

 And yes, core dumps are potentially useful for debugging.

 However, given you're asking that question, and getting core 
 dumps, then it might be easier for you to use the -g option 
 when you compile, and then run your executable (or a.out) 
 through a debugger:

 https://www.youtube.com/watch?v=vcVmWbYEIsk

I am on Ubuntu 16.04. Thanks, I didn't know that "producing a 
core file" was configurable, and it appears that it isn't.

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 11/12/2017 10:25 PM, Tony wrote:

 "Segmentation fault (core dumped)"



I've been assuming that if it says "dumped", the core is dumped.

 I am on Ubuntu 16.04. Thanks, I didn't know that "producing a core file"
 was configurable, and it appears that it isn't.

It is. If you search for "where is core file ubuntu" you will hit the 
output of 'man core', as well as answers like the following, which 
explains that the file may be under /var/cache/abrt:

 
https://stackoverflow.com/questions/2065912/core-dumped-but-core-file-is-not-in-current-directory

Ali

Tony <tonytdominguez aol.com> writes:

On Monday, 13 November 2017 at 07:38:14 UTC, Ali Çehreli wrote:
 On 11/12/2017 10:25 PM, Tony wrote:

 "Segmentation fault (core dumped)"



 I've been assuming that if it says "dumped", the core is dumped.

 I am on Ubuntu 16.04. Thanks, I didn't know that "producing a

 core file"
 was configurable, and it appears that it isn't.

 It is. If you search for "where is core file ubuntu" you will 
 hit the output of 'man core', as well as answers like the 
 following, which explains that the file may be under 
 /var/cache/abrt:


 https://stackoverflow.com/questions/2065912/core-dumped-but-core-file-is-not-in-current-directory

 Ali

My mistake. When I said "and it isn't", I was trying to say "and 
it isn't set on my system as shown by 'ulimit -a'".

Tony <tonytdominguez aol.com> writes:

On Monday, 13 November 2017 at 07:38:14 UTC, Ali Çehreli wrote:

 It is. If you search for "where is core file ubuntu" you will 
 hit the output of 'man core', as well as answers like the 
 following, which explains that the file may be under 
 /var/cache/abrt:


 https://stackoverflow.com/questions/2065912/core-dumped-but-core-file-is-not-in-current-directory

Thanks for the "man core" tip and the link.

codephantom <me noyb.com> writes:

On Monday, 13 November 2017 at 06:25:20 UTC, Tony wrote:
 I am on Ubuntu 16.04. Thanks, I didn't know that "producing a 
 core file" was configurable, and it appears that it isn't.

ok. that's because Ubuntu is not (by default) setup for 
developers.

But you can enable core dump for your executable easily enough.

e.g, if you out file is a.out, then do this:

ulimit -S -c unlimited a.out
(now run your program, and you'll get core file in the same dir 
where the program is)
(this won't be remembered after a reboot, so just do it when/as 
required).

You can view the core file using > objdump -s core

Good luck understanding the contents of that ;-)

Core dumps typically require some specialised expertise to 
analyse.

Unless you're one of those specialists, then better to just run 
your a.out through the debugger, and forget about the core dump 
(until you can't)  ;-)

Antonio Corbi <acorbi ggmail.xml> writes:

On Monday, 13 November 2017 at 09:49:29 UTC, codephantom wrote:
 On Monday, 13 November 2017 at 06:25:20 UTC, Tony wrote:
 I am on Ubuntu 16.04. Thanks, I didn't know that "producing a 
 core file" was configurable, and it appears that it isn't.

 ok. that's because Ubuntu is not (by default) setup for 
 developers.

 But you can enable core dump for your executable easily enough.

 e.g, if you out file is a.out, then do this:

 ulimit -S -c unlimited a.out
 (now run your program, and you'll get core file in the same dir 
 where the program is)
 (this won't be remembered after a reboot, so just do it when/as 
 required).

 You can view the core file using > objdump -s core

 Good luck understanding the contents of that ;-)

 Core dumps typically require some specialised expertise to 
 analyse.

 Unless you're one of those specialists, then better to just run 
 your a.out through the debugger, and forget about the core dump 
 (until you can't)  ;-)

Hi,

core files can be used to do a 'post-mortem' debug session with 
gdb, from 'man gdb':

  You can also start with both an executable program and a core 
file
  specified:

                gdb program core

If your program is compiled with '-g' option, gdb will load the 
executable and extract the information from the core file and it 
will show your program's state exactly as if it had been run from 
the debugger and had failed in that exactly moment.

Antonio