AIX Version 4.3 Differences Guide

Motif 2.1 has been optimized to generate fewer mouse events from the X server
when using gadgets.
8.3.4.17 UIL Extensibility and Portability
Since OSF introduced an extensibility framework, it was necessary to reflect that
in the UIL language. Once a developer has developed a new widget, that new
widget should be usable from UIL as well. However, they should not have to
generate a new compiler for every new widget supported. It was, therefore,
necessary for OSF to develop a mechanism such that the UIL compiler could
dynamically incorporate new widgets to be accepted in UIL source files and
generate the appropriate binary UID code.
In the past, OSF received numerous enhancements requests because the UID
files in the 1.x releases were not architecture neutral. You had to compile the
same UIL source file for every target platform. Moreover, only 32-bit platforms
were supported.
With OSF/Motif 2.1, OSF developed a new UIL technology that reaches those
three objectives simultaneously:
• The UIL compiler can be told to dynamically accept new widgets.
• The UID files generated by the compiler are architecture neutral.
Note that the architecture neutral format is still dependent on 32-bit versus 64-bit
architectures. A UIL file compiled on a 32-bit architecture can be read on any
other 32-bit architecture but not on a 64-bit architecture. Similarly, a UIL file
compiled on a 64-bit architecture can be read on any other 64-bit architecture but
not on a 32-bit architecture. This design decision was made because the memory
used for 64-bit architectures is about twice the size of that used on 32-bit, and
32-bit platforms should not have to bear a 100 percent penalty.
8.3.5 Compatibility with Motif 1.2 and 2.0
As stated at the beginning of this chapter, compatibility with CDE/Motif 1.2 was
given greater emphasis than compatibility with OSF/Motif 2.0. The following
issues should be noted concerning compatibility with Motif 1.2:
• If a customer application subclasses a widget in the group of DrawingArea,
Label, List, Manager, or Primitive, there is a potential for binary incompatibility.
The Class Records for these widgets changed from Motif 1.2 to Motif 2.0. The
only resolution in this instance is to re-compile, unless the application writer
used XmResolvePartOffsets (now known as XmeResolvePartOffsets in the
Motif 2.1 Widget Writer’s Guide).
• The XmString definition has changed in Motif 2.1. It is now a union instead of
a typedef of char *. Existing Motif applications running on Motif 2.1 may have
problems depending upon their usage of XmString.
Some OSF/Motif 2.0 applications may experience problems because of the
following changes:
• The XmCSText widget has been withdrawn, as have those APIs added to
OSF/Motif 2.0 solely to support it.
• Mrm support for word size-independent .uid files has been removed. Existing
.uid files compiled with Motif 2.0 UIL may not be readable. As in OSF/Motif
1.2, .uid files are portable only between machines with the same word size.
Graphical Environment Enhancements 225