Atom

This ambiguous form is most commonly used and shows all matching documents. For example:

?- help(append).

Name / Arity

Give help on predicates with matching Name/Arity. Arity may be unbound.

Name // Arity

Give help on the matching DCG rule (non-terminal)

Module:Name

Give help on predicates with Name in Module and any arity. Used for loaded code only.

Module:Name/Arity

Give help on predicates with Name in Module and Arity. Used for loaded code only.

f(Name/Arity)

Give help on the matching Prolog arithmetic functions.

c(Name)

Give help on the matching C interface function

section(Label)

Show the section from the manual with matching Label.

xpce(Class, Kind, Name)

Show the documentation of an XPCE class member.

help/1 shows documentation from the manual as well as from loaded user code if the code is documented using PlDoc. To show only the documentatoion of the loaded predicate we may prefix predicate indicator with the module in which it is defined.

If an exact match fails this predicates attempts fuzzy matching and, when successful, display the results headed by a warning that the matches are based on fuzzy matching.

If possible, the results are sent through a pager such as the less program. This behaviour is controlled by the Prolog flag help_pager. See section level documentation.

If the terminal supports hyperlinks (see the Prolog flag hyperlink_term), the manual references in the page are clickable. In an Epilog window, clicking one quits the pager and runs help/1 on the linked object.

See also

- apropos/1 for searching the manual names and summaries.