What’s a Core Dump?
It’s a file created when your program terminates abnormally. It contains a snapshot of the program’s state at the time of the failure.
What does it look like?
On Linux it will appear in the same location as the executable and will be named something like:
core.4196
Where the number is the process id of the program while it was running.
And what can I do with it?
You can have a look at it using GDB! GDB can read a core file to give you valuable information about a crash after the event.
Some Linux distributions have the ability to create core files disabled by default – you need to type:
ulimit -c unlimited
before running the program to allow the creation of the core file when the program terminates.
To examine a core file, just pass it to gdb:
gdb core.324
GDB will load up all the info and it will look as though you have just run the program and seen the error. You’ll be able to view a backtrace and a range of other information, but it will be a frozen “snapshot” of execution.
Instant debugging!