### 7.2 Term unification

- `(=)/2` - Prolog unification
- `unify_with_occurs_check/2`
- `(``\``=)/2` - not Prolog unifiable

#### 7.2.1 `(=)/2` - Prolog unification

Templates

  `=(?term, ?term)`

Description

`Term1 = Term2` unifies `Term1` and `Term2`. No occurs check is done, i.e. this predicate does not check if a variable is unified with a compound term containing this variable (this can lead to an infinite loop).

`=` is a predefined infix operator (section 7.14.10).

Errors

None.

Portability

ISO predicate.

#### 7.2.2 `unify_with_occurs_check/2`

Templates

  `unify_with_occurs_check(?term, ?term)`

Description

`unify_with_occurs_check(Term1, Term2)` unifies `Term1` and `Term2`. The occurs check test is done (i.e. the unification fails if a variable is unified with a compound term containing this variable).

Errors

None.

Portability

ISO predicate.

#### 7.2.3 `(\=)/2` - not Prolog unifiable

Templates

  `\=(?term, ?term)`

Description

`Term1 \= Term2` succeeds if `Term1` and `Term2` are not unifiable (no occurs check is done).

`\=` is a predefined infix operator (section 7.14.10).

Errors

None.

Portability

ISO predicate.

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