decval(++ElemSpec)

ElemSpec

Atom or ground compound term whose arguments are non negative integers.

Description

If ElemSpec is an atom, it must specify a non-logical variable visible from the context module.

If ElemSpec is a compound term, it must specify an element visible array. All its arguments must be non negative integer smallers than the bound specified with array/1/2 or variable/1.

In a multithreaded setting, this operation can be considered atomic.

Modes and Determinism

• decval(++) is det

Modules

Exceptions

(4) instantiation fault

ElemSpec is not instantiated.

(5) type error

ElemSpec is a structure whose arguments are not all integers.

(5) type error

ElemSpec is neither an atom nor a ground structure.

(5) type error

The value or type of ElemSpec is not integer.

(6) out of range

Array index in ElemSpec is out of bounds.

(41) array or global variable does not exist

ElemSpec does not designate an existing array or variable.

Examples

Success:
      [eclipse]: local(array(a(4), prolog)),
              setval(a(0), -2),
              decval(a(0)),
              getval(a(0),X).
      X = -3
      yes.

      [eclipse]: local(array(g(4, 5), integer)),
              decval(g(3, 2)),
              getval(g(3, 2), X).
      X = -1
      yes.

      [eclipse]: setval(a, 3),
              decval(a),
              getval(a, X).
      X = 2
      yes.

Error:
      decval(X).                          (Error 4).
      setval(a, 2.0),
          decval(a).                      (Error 5).
      local(array(a(2), float)),
          decval(a(1)).                   (Error 5).
      local(array(a(2))),
          decval(a(2)).                   (Error 6).
      decval(no_var).                     (Error 41).
      decval(noarray(2, 4)).              (Error 41).

See Also