Learning PostgreSQL 11 - Third Edition

Creating a function in the C language

In the following example, we will create a factorial function in the C language. This can be used as a template for creating more complex functions. You can create a PostgreSQL C function in four steps, as follows:

1. Install the postgresql-server-development library.
2. Define your function in C, create a make file, and compile it as a shared library (.so).

3. Specify the location of the shared library that contains your function. The easiest way to do this is to provide the library's absolute path when creating the function or to copy the function-shared library that's created to the PostgreSQL library directory.
4. Create the function in your database by using the CREATE FUNCTION statement.

To install the ...