XVT is a software development environment for building cross-platform GUI applications in C or C++. XVT allows developers to graphically lay out an application's GUI, and provides cross-platform libraries to aid development.
XVT currently supports the Microsoft Windows, Linux, Mac OS X, Solaris, HP-UX, and AIX platforms. With XVT, applications can be designed and developed once and then subsequently compiled on any of these platforms. XVT also allows programs to be built to run across a network, meaning that the processing would take place on a local host but the user interface would take place a remote host.
XVT has been in development since 1989 and has provided a cross-platform software development toolkit for the majority of that time. XVT software is utilized in a number of mission-critical production sites and applications.
Their approach is not as a widget replacement look-alike set, but acts more like a universal API translator. XVT is an "abstraction layer" that removes the developer from being concerned with which OS the application will run on. When your application is compiled, the XVT API points to the native controls/widgets for the OS on which you are compiling your code. This matters to OS user-purists, who can be very fussy when the views "aren't quite right." It also allows you to build applications that will adapt whatever user themes the OS allows users to set.
There are other uses of this product beyond cross platform development (though it does this well). As a CASE tool, a non-programmer business analyst can actually lay out all the user interfaces, review them with end users and subject matter experts in a RAD-like (Rapid Application Development) requirements capture by functional review, and then the XVT architect tool will deliver the C or C++ (ANSI-compliant) code. This would take a bit of familiarity with a compiler and the layout tools, but it would allow programmers to be relieved of coding GUI and focus their work on the business logic, event handling, etc.
Version 5.8 release notes indicate that the product developers are concerned with ease of use issues, but there are some things that still need improvement. The strata tools are the old fashioned pop-up window-with-a-million-tabs. Maybe something docked on the side that is handier and visibly available. GTK+ is not released yet, nor Mac Cocoa (though these are due out this year?). It does work with Vista, but as all Vista apps are discovering, the help file format needs a viewer from Microsoft for win32 that Microsoft chose not to include. This hurts backwards compatibility with existing help files (though it is fairly simple to find and download the Microsoft .hlp viewer).