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# atom_length(+Atom, -Length)

Succeeds if Length is the length of Atom.

Atom
  Atom.
Length
  Integer or variable.

## Description

The length of an atom Atom is unified with Length. The length of an atom is the number of characters in the atom's name.

### Modes and Determinism

- atom_length(+, -) is det

### Exceptions

(4) instantiation fault
  Atom is not instantiated (non-coroutine mode only).
(5) type error
  Atom is instantiated, but not to an atom.
(5) type error
  Length is neither an integer nor a variable.

## Examples

    Success:
          atom_length(test, 4).
          atom_length(test,L).         (gives L = 4).
          atom_length(as, X).          (gives X = 2).
          atom_length('4', 1).

    Fail:
          atom_length(test, 5).

    Error:
          atom_length(Atom, 2).        (Error 4).
          atom_length(Atom, 2.0).      (Error 5).
          atom_length(4, 1).           (Error 5).
          atom_length(as, 2.0).        (Error 5).

## See Also

atom / 1, atom_string / 2, string_length / 2