How are sockets used for connections/streaming between application NOT over a network?

Question

I have heard that sockets are used for all sorts of streaming between applications to send and receive data.

I have always thought and even read from articles that aim to give a "general sense" that sockets are used to create connections over networks.

However recently I saw that sockets are also used for local streaming/connections between apps which are not over a network.

My question;

• How are sockets used for connections/streaming NOT over a network between apps?

Answer 1

If the applications are on the same machine then you can use the localhost or loopback address 127.0.0.1 as the IP address of the socket and any port number > 1024 in both applications and then they can communicate over this connection .

Answer 2

Also, if you want to use the socket approach and on linux, AF_UNIX is better than inet socket as they avoid some level of inet specific tasks like routing/adding-removing ip and transport headers, etc