The Scroll Bar widget provides the means of partially displaying data which is too large to display in full. The Scroll Bar can be used to create a logical viewpoint onto a second widget which contains the data.
Contained within the Scroll Bar is a slider which can be moved by the user; movements of the slider are meant to change the viewpoint onto the displayed data. Further, the size of the slider with respect to the Scroll Bar is supposed to represent how much of the displayed data is currently in view: it is thus a visual clue of the relationship between the logical viewpoint and the displayed data.
Several Motif widgets contain Scroll Bars as part of their structure, namely the scrolled window, scrolled text, or scrolled list widgets.
For more information, consult XmScrollBar(3X) in the OSF/Motif Programmer's Reference.
NOTES
It is much easier to use a scrolling widget provided directly by Motif than implementing a logical viewpoint yourself: you are advised to use these widgets whenever possible.
See also: