One of the great features of PostgreSQL is its extendability. My colleague and senior PostgreSQL developer Ibar has blogged about developing an extension with much broader capabilities including callback functionality. But in this blog post, I am trying to address a complete novice user who has never tried but wants to develop a simple function [&]

https://www.percona.com/blog/2019/07/31/postgresql-simple-c-extension-development-for-a-novice-user/