X Window System interface in the MVS environment: Application resource file

With the X Window System, you can modify certain characteristics of an application at run time by means of application resources. Typically, application resources are set to tailor the appearance and possibly the behavior of an application. The application resources can specify information about an application’s window sizes, placement, coloring, font usage, and other functional details.

On a UNIX system, this information can be found in the user’s home directory in a file called .Xdefaults. In the MVS™ environment, this data set is called user_id .X.DEFAULTS. Each line of this data set represents resource information for an application.

Note: For information about the application resource file in z/OS UNIX System Services, see X Window System routines: z/OS UNIX System Services support.

Figure 1 shows an example of a set of resources specified for a typical X Window System application.

Figure 1. Resources specified for a typical X Window System application

XClock*geometry:      500x60+5-5
XClock*font:          -bitstream-*-bold-r-*-33-240-*
XClock*foreground:    orange
XClock*background:    skyblue
XClock*borderWidth:   4
XClock*borderColor:   blue
XClock*analog:        false

In this example, the xclock application automatically creates a window in the lower left corner of the screen with a digital display in orange letters on a skyblue background.

These resources can also be set on the RESOURCE_MANAGER property of the X server, which allows a single, central place where resources are found, that control all applications, displayed on an X server. You can use the xrdb program to control the X server resource database in the resource property.

xrdb is an X client that you can use either to get or to set the contents of the RESOURCE_MANAGER property on the root window of screen 0. This property is then used by all applications at startup to control the application resource.