GLib

Not to be confused with glibc, the GNU implementation of the C standard library or gnulib, a portability library.

GLib

Developer(s)	The GNOME Project et al.
Stable release	2.46.2 (November 10, 2015 (2015-11-10)) [±]
Development status	Active
Written in	C
Operating system	Linux, Unix-like, OS X, Microsoft Windows
Platform	Cross-platform
Type	Library
License	GNU Lesser General Public License
Website	wiki.gnome.org/Projects/GLib

As the GNU C Library serves as a wrapper for Linux kernel system calls, so do the libraries bundled in GLib (GObject, Glib, GModule, GThread and GIO) serve as further wrappers for their specific tasks.

Simplified software architecture of GTK+. Pango, GDK, ATK, GIO, Cairo and GLib.

GLib is a bundle of five low-level system libraries written in C and developed mainly by GNOME. GLib code was separated from GTK+, so it can be used by software other than GNOME and has been developed in parallel ever since.

Features

GLib provides advanced data structures, such as memory chunks, doubly and singly linked lists, hash tables, dynamic strings and string utilities, such as a lexical scanner, string chunks (groups of strings), dynamic arrays, balanced binary trees, N-ary trees, quarks (a two-way association of a string and a unique integer identifier), keyed data lists, relations and tuples. Caches provide memory management.

GLib implements functions that provide threads, thread programming and related facilities such as primitive variable access, mutexes, asynchronous queues, secure memory pools, message passing and logging, hook functions (callback registering) and timers. Also message passing facilities such as byte order conversion and I/O channels.

Some other features of GLib include:

• standard macros
• warnings and assertions
• dynamic loading of modules

Components

The GLib package consisted of 5 libraries, but they were all merged into one library (since then simply known as Glib), and are no longer sustained as standalone libraries. The five original libraries were:

• GObject – an object system, includes the type system GType
• Glib
• GModule
• GThread
• GIO

History

GLib began as part of the GTK+ project. However, before releasing GTK+ version 2, the project's developers decided to separate non-GUI-specific code from GTK+, thus creating GLib as a separate software bundle. GLib was released as a separate library so other developers, those who did not make use of the GUI-related portions of GTK+, could make use of the non-GUI portions of the library without the overhead of depending on the entire GUI library.

Since GLib is a cross-platform library, applications using it to interface with the operating system are usually portable across different operating systems without major changes.

Releases

For a current overview see Roadmap 2.24–2.36 and 2.38–current, for details see the respective release notes in the mailing list or in the tarballs directory.

Release series	Initial release date	Major enhancements
GLib 1.x
1.1	1998-09-12
1.2	1999-02-27
1.3	2001-09-25
GLib 2.x
2.0	2002-03-08
2.24	2010-03-26	GVariant, GConverted
2.26	2010-09-27	GSettings, GDbus, GObject property bindings (GAtomic for refcounting)
2.30	2011-09-26	Non-unique GApplications, use eventfd() for mainloop wakeup, GHashTable set optimization, GObject data scalability
2.32	2012-03-24	Plans for GLib 2.32
2.38	2013-09-23	applications launched using D-Bus activation GSubprocess, Unicode 6.3 (released September 2013)
2.40	2014-03-24	GNotification, System notification API
2.42	2014-09-22

Similar projects

Other widget toolkits provide low-level functions and implementations of data structures as well, e.g.:

• STL – C++ alternative to GObject
• Boost – provides some functionality for C++, such as threading primitives, similar to what GLib does for C.
• wxBase – non-GUI functions of the wxWidgets library
• The Apache Portable Runtime and Apple Core Foundation have a large functional overlap with GLib, and provide many similar OS-portable threading, network and data structure implementations in C.

External links

• GLib API documentation
• GLib Git Source Tree