◄Directive Summary►  ◄Summary►
──────────────────────────────────────────────────────────────────────────────
 
  Syntax:  .ERRDIF[I] <argument1>, <argument2>
           .ERRIDN[I] <argument1>, <argument2>
 
  .ERRDIF generates a severe error if argument1 and argument2 are
  different. .ERRIDN generates an error if they are identical. These
  directives are commonly used inside macros, to test for bad values
  passed as parameters. .ERRDIFI and .ERRIDNI do the same actions, but
  are case-insensitive.
 
  argument1 and argument2 can each be a symbolic name, number, or
  expression.
 
  See Also:  .ERR, .ERR1, .ERRB, .ERRDEF, .ERRE, .ERRNZ
                                    -♦-