Generated by abort(3). This signal by default causes your program to terminate and dump core.
abort(3), is often called indirectly by assert(3). Basically this usually means that the program detected an illegal state and has aborted allowing for debugging.
You can often also generate a SIGABRT with Ctrl-\, useful if you are trying to debug an infinite loop. (Run the program, wait for it to "hang" press Ctrl-\ or kill -ABRT pid, and then use gdb(1) to inspect the core file).
