Class variables act as read-only storage for class-constants. They
are normally used for storing setting information, such as fonts,
colours etc. For this reason, the default value for a class_variable
is defined with the declaration of it, but this default my be overruled
using the Defaults file. The system defaults file is
located in the XPCE home directory (`@pce<-home').
This file contains an
include statement, including the file /.xpce/Defaults,10On
Windows systems, expands to %HOME%, %USERPROFILE%, %HOMEDRIVE%/%HOMEPATH%
or the root of the current drive. See expand_file_name/2
of the SWI-Prolog manual. which may be used by the
developer and application user to specify defaults.
Many XPCE built-in classes define class-variables. These can be examined using the ClassBrowser (see section 3.3.1) from the online manual tools.