A PIGUI (Platform Independent Graphical User Interface) package is a software library that a programmer uses to produce GUI code for multiple computer platforms. The package presents subroutines and/or objects (along with a programming approach) which are independent of the GUIs that the programmer is targeting. For software to qualify as PIGUI it must support several GUIs under at least two different operating systems (e.g. just supporting OPEN LOOK and X11 on two Unix boxes doesn't count). The package does not necessarily provide any additional portability features. Native look and feel is a desirable feature, but is not essential for PIGUIs. Considerations Using a PIGUI has limitations, such as the PIGUI only deals with the GUI aspects of the program so the programmer responsible for other portability issues, most PIGUIs slow the execution of the resulting code, and programmers are largely limited to the feature set provided by the PIGUI. Dependence on a PIGUI can lead to project difficulties since fewer people know how to code any specific PIGUI than do a platform-specific GUI, limiting the number of people who can give advanced help, and if the vendor goes out of business there may be no further support, including future OS enhancements, though availability of source code can ease but not eliminate this problem. Also, bugs in any package, including the PIGUI, filter down to production code. Alternative approaches Web browsers offer a convenient alternative for many applications. Web browsers utilize HTML as a presentation layer for applications hosted on a central server, and web browsers are available for pretty much every platform. However, some applications do not lend themselves well to the web paradigm, requiring a local application with GUI capabilities. Where such applications must support multiple platforms, PIGUI can be more appropriate. Instead of using a PIGUI, developers could partition their applications into GUI and non-GUI objects, and implement the GUI objects in the native API. Then, when porting, only the GUI objects need to be rewritten for the new platform. There are some software developers who recommend this course of action, as it produces a better fit on each platform and eliminates the overhead often associated with PIGUI toolkits. Obviously, this may require more effort in both the initial development and in ongoing maintenance (no single base of source code). It also means learning how to code for every target platform, which is not (usually) a trivial