Along with the extension installation script file, you must provide a .control file. The .control file for our example postal.control looks like this:

# postal address processing extension
comment = 'utilities for postal processing'
default_version = '1.0'
module_pathname = '$libdir/postal'
relocatable = true
requires = 'plpgsql'

The purpose of the .control file is to provide a description of your extension. This metadata may include directory, default_version, comment, encoding, module_pathname, requires, superuser, relocatable, and schema.

The main PostgreSQL documentation for this file is located at http://www.postgresql.org/docs/current/static/extend-extensions.html.

This example shows the requires configuration parameter. Our extension depends on the procedural language PL/pgSQL. On most platforms, it is installed by default. Unfortunately, it is not installed on all platforms, and nothing should be taken for granted.

Multiple dependencies can be indicated by separating...