IUP is a multi-platform toolkit for building graphical user interfaces. It offers APIs in three basic languages: C, Lua and LED.

Its library contains about 100 functions for creating and manipulating dialogs.

IUP's purpose is to allow a program to run in different systems without changes - the toolkit provides the application portability. Supported systems include: GTK+, Motif and Windows.

IUP uses an abstract layout model based on the boxes-and-glue paradigm from the TEX text editor. This model, combined with the dialog-specification language (LED) or with the Lua binding (IupLua) makes the dialog creation task more flexible and independent from the graphics system's resolution.

Currently available interface elements can be categorized as follows:

Hence IUP has some advantages over other interface toolkits available:

IUP is free software, can be used for public and commercial applications.


The library is available for several compilers:

The library is available for several operating systems:


The official support mechanism is by e-mail, using Before sending your message:

If all these points were checked, you can report your problem. Please specify in your message: function, attribute, callback, platform and compiler.

We host the IUP support features at SourceForge: It provides us Mailing List, SVN Repository and Downloads.

The discussion list is available at:
Source code, pre-compiled binaries and documentation can be downloaded at:
The SVN can be browsed at:

If you want us to develop a specific feature for the toolkit, Tecgraf is available for partnerships and cooperation.

Lua documentation and resources can be found at


This work was developed at Tecgraf by means of the partnership with PETROBRAS/CENPES.

Library Authors:

We must also mention engineer Enio Emanuel Russo, from PETROBRAS, who effectively contributed to the system's specification and project.

We would like to thank all the people from Tecgraf that directly worked or strategically contributed to the library:

Thanks for SourceForge for hosting the support features. Thanks for the LuaForge team for previously hosting the support features for many years.

IUP is registered at the National Institute of Intellectual Property in Brazil (INPI) under the number 07569-0, and so it is protected against illegal use. The registration is valid internationally. See the Tecgraf Library License for further usage information and Copyright.


This documentation is available at and

The full documentation can be downloaded from the Download Files. The documentation is also available in Adobe Acrobat and Windows HTML Help formats.

The HTML navigation uses the WebBook tool, available at

There are also a few presentations:


This product stimulated the following scientific publications:

Interview at the FLOSS weekly show about Free Libre Open Source Software, hosted by Randal Schwartz, in Nov 9th 2011: