Product
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:
  - Primitives (effective user interaction): dialog, label, button, text, multi-line, list, toggle, canvas, frame, image.
- Composition (ways to show the elements): hbox, vbox, zbox, fill.
- Grouping (definition of a common functionality for a group of elements):
  radio.
- Menu (related both to menu bars and to pop-up menus): menu, submenu, item, separator.
- Additional (elements built outside the main library): dial, gauge, matrix, tabs, valuator, OpenGL canvas, color 
    chooser, color browser.
- Dialogs (useful predefined dialogs): file selection, message, alarm, data input, list selection.
Hence IUP has some advantages over other 
  interface toolkits available:
  - Simplicity: due to the small number of functions and to its attribute mechanism, the learning curve 
    for a new user is often faster.
- Portability: the same functions are implemented in each one of the platforms, thus assuring the 
    interface system's portability.
- Customization: the dialog specification language (LED)
    and the Lua binding (IupLua)
    are two mechanisms in which it is possible 
    to customize an application for a specific user with a simple-syntax text file.
- Flexibility: its abstract layout mechanism provides flexibility to dialog creation.
- Extensibility: the programmer can create new interface elements as needed.
IUP is free software, can be used for public and commercial applications.
The library is available for several compilers: 
  - GCC and CC, in the UNIX environment 
- Visual C++, Borland C++, Watcom C++ and GCC (Cygwin and MingW), in the Windows environment
The library is available for several operating systems:
  - UNIX (SunOS, IRIX, and AIX) using Motif 2.x
- UNIX (FreeBSD and Linux) using GTK+ (since 3.0)
- Microsoft Windows XP/2003/Vista/7 using the Win32 API
The official support mechanism is by e-mail, using 
iup@tecgraf.puc-rio.br. 
  Before sending your message:
  - Check if the reported behavior is not described in the user guide. 
- Check if the reported behavior is not described in the specific control or driver characteristics. 
  
- Check the History to see if your version is updated. 
- Check the To Do list to see if your problem has already been reported.
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:
	http://sourceforge.net/projects/iup/. It provides us  
  Mailing List, SVN Repository and Downloads.
  
    The discussion list is available at:
    http://lists.sourceforge.net/lists/listinfo/iup-users.
    Source code, pre-compiled binaries and documentation can be downloaded at: 
	http://sourceforge.net/projects/iup/files/.
    The SVN can be browsed at: 
	https://sourceforge.net/p/iup/iup/.
  
  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
http://www.lua.org/.
This work was developed at Tecgraf by means of the partnership with PETROBRAS/CENPES.
  Library Authors:
	- Marcelo Gattass
- Luiz Henrique de Figueiredo
- Carlos Henrique Levy
- Antonio Scuri
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:
	- André Carregal
- André Clinio
- André Costa
- André Derraik
- Camilo Freire
- Carlos Augusto Mendes
- Carlos José Pereira de Lucena
- Claudio Coutinho de Biasi
- Diego Nehab
- Diogo Martinez
- Guilherme Fonseca Alvarenga
- Henrique Dalcin Mendes Pinheiro
- Leonardo Constantino Oliveira
- Luiz Cristóvão Gomes Coelho
- Luiz Martins
- Mark Stroetzel Glasberg
- Mauricio Oliveira Carneiro
- Milton Jonathan
- Neil Armstrong Rezende
- Rafael Rieder 
- Renato Borges
- Renato Cerqueira
- Roberto Beauclair
- Tomas Guisasola Gorham
- Vinicius Almendra
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 http://www.tecgraf.puc-rio.br/iup 
and
http://iup.sourceforge.net/
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
  http://www.tecgraf.puc-rio.br/webbook.
There are also a few presentations:
This product stimulated the following 
  scientific publications:
  - Scuri, A. "IUP - Portable User Interface". Software Developer's Journal. Dec/2005.  
	[iup_sdj2005.pdf]
- Levy, C. H.; Figueiredo, L. H.; Gattass, M.; Lucena, C.; and Cowan, D. "IUP/LED: A Portable User Interface 
    Development Tool". Software: Practice & Experience, 26 #7 (1996) 737-762. [spe95.pdf]
- Oliveira Prates, R.; Figueiredo, L. H.; and Gattass, M. "Especificação de Layout Abstrato por Manipulção 
    Direta". Proceedings of VII SIBGRAPI (1994), 165-172. [sib94.pdf 
	in Portuguese]
- Oliveira Prates, R.; Gattass, M. ;and Figueiredo, L. H. "Visual LED: uma ferramenta interativa para geração de 
    interfaces gráficas". M.Sc. dissertation, Computer Science Department, PUC-Rio, 1994. [prates94.pdf 
	in Portuguese]
    
- Levy, C. H. "IUP/LED: Uma Ferramenta Portátil de Interface com Usuário".
    M.Sc. dissertation, Computer Science 
    Department, PUC-Rio, 1993.[levy93.pdf 
	in Portuguese]
- Figueiredo, L. H.;Gattass, M.; and Levy, C.H. "Uma Estratégia de Portabilidade para Aplicações Gráficas 
    Interativas".
    Proceedings of VI SIBGRAPI (1993), 
    203-211. [sib93.pdf in Portuguese]
Interview at the FLOSS weekly 
show about Free Libre Open Source Software, hosted by
Randal Schwartz, in Nov 9th 2011: