[ Thanks to Kevin
Reichard for this link. ]
“Motif is a C-language API (a library) for creating
graphical applications under the X Window System. Motif acts as a
layer above the X Toolkit Intrinsics and the low-level X Library.
That probably seems like old hat or ancient history to many
readers.“
“When the X Window System first came out, it provided one of the
few cross-platform graphics systems. I remember being amazed at
seeing the Cray Research (back then there was a Cray Research)
demonstration room filled with workstations from every UNIX vendor,
all running the same graphical software. Of course, the Cray folks
were trying to highlight that you could use their supercomputers
with a wide variety of computers. Instead, I saw true
cross-platform portability and became an instant convert, dropping
HPwindows, SunView, and other proprietary windowing systems like
the plague.”
“At the time, the main X API was the low-level X Library, or
Xlib. Programming in Xlib is just a few steps below programming
using only the Win32 API; it’s very low level. The main abstraction
layer on top of the Xlib was the X Toolkit Intrinsics, or Xt. The
Xt library added the concept of a widget, a user interface element
such as a menu, push button, or scroll bar. Remember, all of this
was written in C before C++ gained widespread acceptance. Even so,
Xt provides an inheritance system with the ability to overload
methods, using C language function pointers.”