Elektra  0.8.12
The Elektra API

Elektra Initiative Overview

Elektra provides a universal and secure framework to store configuration parameters in a global, hierarchical key database. The core is a small library implemented in C. The plugin-based framework fulfills many configuration-related tasks to avoid any unnecessary code duplication across applications while it still allows the core to stay without any external dependency. Elektra abstracts from cross-platform-related issues with an consistent API, and allows applications to be aware of other applications' configurations, leveraging easy application integration.

See the website for more information http://www.libelektra.org

API docu

This document occupies with the API implementation, documentation, internals and plugins. On the one hand it gives an overview and an introduction for developers using Elektra, on the other hand it gives an informal descriptions what methods must and may provide to allow an alternative implementation of the API.

The current version (for stable releases) of this document can be found at http://doc.libelektra.org/api/current/html

The latest version (from git master) of this document can be found at http://doc.libelektra.org/api/latest/html

Using the Elektra Library

A C or C++ source file that wants to use Elektra should include:

#include <kdb.h>

To link an executable with the Elektra library, one way is to use the pkg-config tool:

$ gcc -o application `pkg-config --cflags --libs elektra` application.c

Another way is to use CMake:

find_package(Elektra REQUIRED)
include_directories (${ELEKTRA_INCLUDE_DIR})
target_link_libraries (application ${ELEKTRA_LIBRARIES})

Elektra API

The API was written in pure C because Elektra was designed to be useful even for the most basic system programs.

The API follows an object-oriented design, and there are 3 main classes as shown by the figure:

Elektra Classes
Some general things you can do with each class are:

KDB (Key Database)




There are 5 trees (=namespaces) of keys: spec, proc, dir, user and system that are all unified (in the given order) in one cascading tree starting with /.

The cascading tree is the logical tree to be used in applications. The other trees are the physical ones that stem from configuration sources. When using cascading key the best key will be searched at runtime, which appears like a tree on its own. See Cascading in the documentation of ksLookupByName() how the selection of keys works.

Rules for Key Names

When using Elektra to store your application's configuration and state, please keep in mind the following rules:

Backend Overview

The core of Elektra does not store configuration itself to the harddisk. Instead this work is delegated to backends.

If you want to develop a backend, you should already have some experience with Elektra from the user point of view. You should be familiar with the data structures: Key and KeySet Then you can start reading about Backends that are composed out of Plugins. To get started with writing plugins, first read our plugin tutorial in doc/tutorials!