segmentation fault

segmentation fault
 n.

   [Unix]

   1. [techspeak] An error in which a running program attempts to access
   memory not allocated to it and {core dump}s with a segmentation
   violation error. This is often caused by improper usage of pointers in
   the source code, dereferencing a null pointer, or (in C) inadvertently
   using a non-pointer variable as a pointer. The classic example is:

   int i;
   scanf ("%d", i);  /* should have used &i */

   2. To lose a train of thought or a line of reasoning. Also uttered as
   an exclamation at the point of befuddlement.
    

segmentation fault
segfault

   An error in which a running {Unix} program attempts to access
   memory not allocated to it and terminates with a segmentation
   violation error and usually a {core dump}.

   [{Jargon File}]

   (1994-12-15)