dereference

dereference

   <programming> To access the thing to which a pointer points,
   i.e. to follow the pointer.  E.g. in {C}, the declarations

   	int i;
   	int *p = &i;

   declare i as an integer and p as a pointer to integer.  p is
   initialised to point at i ("&i" is the address of i - the
   inverse of "*").  The expression *p dereferences p to yield i
   as an {lvalue}, i.e. something which can appear either on the
   left of an {assignment} or anywhere an integer expression is
   valid.  Thus

   	*p = 17;

   would set i to 17.  *p++ is not the same as i++ however since
   it is parsed as *(p++), i.e. increment p (which would be an
   invalid thing to do if it was pointing to a single int, as in
   this example) then dereference p's old value.

   The {C} operator "->" also dereferences its left hand argument
   which is assumed to point to a {structure} or {union} of which
   the right hand argument is a {member}.

   At first sight the word "dereference" might be thought to mean
   "to cause to stop referring" but its meaning is well
   established in jargon.

   (1998-12-15)