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Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

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.. rst-class:: align-right

built-in method

.. index:: pair: message_hook/4; Built-in method .. _methods_message_hook_4:

message_hook/4

Description

::

message_hook(Message, Kind, Component, Tokens)

User-defined hook method for intercepting printing of a message, declared in the :ref:`logtalk apis:logtalk/0` built-in object as a public, multifile, and dynamic predicate. This hook method is automatically called by the :ref:methods_print_message_3 method. When the call succeeds, the print_message/3 method assumes that the message has been successfully printed.

Modes and number of proofs

::

message_hook(@nonvar, @nonvar, @nonvar, @list(nonvar)) - zero_or_one

Errors

(none)

Examples

::

:- multifile(logtalk::message_hook/4). :- dynamic(logtalk::message_hook/4).

% print silent messages instead of discarding them as default logtalk::message_hook(_, silent, core, Tokens) :- logtalk::message_prefix_stream(silent, core, Prefix, Stream), logtalk::print_message_tokens(Stream, Prefix, Tokens).

.. seealso::

:ref:methods_message_prefix_stream_4, :ref:methods_message_tokens_2, :ref:methods_print_message_3, :ref:methods_print_message_tokens_3, :ref:methods_print_message_token_4, :ref:methods_ask_question_5, :ref:methods_question_hook_6, :ref:methods_question_prompt_stream_4