incval(++ElemSpec)

ElemSpec

Atom or ground compound term with non negative integer arguments.

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 a visible array element. all its arguments must be non negative integers smaller than the bounds specified with array/1/2 or variable/1.

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

Modes and Determinism

• incval(++) 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 range.

(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(1), -2),
              incval(a(1)),
              getval(a(1), X).
      X = -1
      yes.

      [eclipse]: local(array(g(4), integer)),
              incval(g(1)),
              getval(g(1), X).
      X = 1
      yes.

      [eclipse]: setval(count, 0),
              repeat,
              writeln(hello),
              incval(count),
              getval(count, X),
              X >= 3, !.
      hello
      hello
      hello
      X = 3
      yes.

Error:

      incval(X).                            (Error 4).
      incval(a(2.0)).                       (Error 5).
      setval(a, 2.0), incval(a).            (Error 5).
      local(array(a(2), float)),
          incval(a(1)).                     (Error 5).
      local(array(a(10), integer)),
          incval(a(-2)).                    (Error 6).
      incval(no_array(0)).                  (Error 41).
      incval(no_var).                       (Error 41).

See Also