%LOC (arg)
  Returns the internal address of a storage item.  The argument can
  be a variable, an expression, or the name of a procedure.  (It must
  not be the name of an internal procedure or statement function.) It
  can be of any data type.  The result is an INTEGER*8 data type.

  In the case of global symbolic constants, %LOC returns the value of
  the constant rather than an address.

  The %LOC built-in function serves the same purpose as the LOC
  intrinsic.