Fan-out (software)
{{Short description|Term used in software engineering}}
{{Unfocused|date=March 2022}}
Fan-out has multiple meanings in software engineering.
Message-oriented middleware
In message-oriented middleware solutions, fan-out is a messaging pattern used to model an information exchange that implies the delivery (or spreading) of a message to one or multiple destinations possibly in parallel, and not halting the process that executes the messaging to wait for any response to that message.{{cite web |url=https://www.rabbitmq.com/tutorials/amqp-concepts.html |title=AMQP 0-9-1 Model Explained |website=RabbitMQ}}{{cite web |url=https://docs.oracle.com/cd/E13161_01/tuxedo/docs10gr3/pgc/pgreq.html#wp1055477 |title=Writing Request/Response Clients and Servers: Sending Asynchronous Messages |work=Oracle Tuxedo Documentation}}{{cite web |url=http://www.linuxtoys.org/fanout/fanout.html |title=/dev/fanout : A One-To-Many Multiplexer}}
Software design and quality assurance
In software construction, the fan-out of a class or method is the number of other classes used by that class or the number of other methods called by that method.{{cite book |last=McConnell |first=Steven |title=Code Complete, Second Edition |year=2004 |isbn=978-0-7356-1967-8 |publisher=Microsoft Press |chapter=Chapter 5: Design Construction |url-access=registration |url=https://archive.org/details/codecomplete0000mcco }}
Additionally, fan-out has impact on the quality of a software.{{Cite book|last1=Alikhashashneh|first1=E.|last2=Raje|first2=R.|last3=Hill|first3=J.|title=2018 1st International Conference on Data Intelligence and Security (ICDIS) |chapter=Using Software Engineering Metrics to Evaluate the Quality of Static Code Analysis Tools |date=April 2018|chapter-url=https://ieeexplore.ieee.org/document/8367641|pages=65–72|doi=10.1109/ICDIS.2018.00017|isbn=978-1-5386-5762-1 |s2cid=44084551 }}{{Cite journal|last=Krauskopf|first=J.|date=February 1990|title=Elemental concerns (software design)|url=https://ieeexplore.ieee.org/document/46811|journal=IEEE Potentials|volume=9|issue=1|pages=13–15|doi=10.1109/45.46811|s2cid=23867273 |issn=1558-1772|url-access=subscription}}{{Cite book|last1=Mubarak|first1=A.|last2=Counsell|first2=S.|last3=Hierons|first3=R. M.|title=2010 Fourth International Conference on Research Challenges in Information Science (RCIS) |chapter=An evolutionary study of fan-in and fan-out metrics in OSS |date=May 2010|chapter-url=https://ieeexplore.ieee.org/document/5507329|pages=473–482|doi=10.1109/RCIS.2010.5507329|isbn=978-1-4244-4839-5 }}