[comp.windows.x] PARENT_WINDOW Environment Variable

ellis@cadillac.siemens.COM (Ellis Cohen) (10/02/87)

                        APPLICATIONS SHOULD USE 
                 THE PARENT_WINDOW ENVIRONMENT VARIABLE

It is generally assumed that a window manager controls the entire screen.
Consequently, all existing applications that we have seen open their top
level windows with the root window of the display as their parent window.
We believe that applications should consider opening their top-level
windows within some other window, and that the PARENT_WINDOW environment
variable be used for this purpose (much as DISPLAY selects the display to
be used).

Specifically, we recommend that

    o If an appplication finds the environment variable PARENT_WINDOW,
        it should open top-level windows in that window.

    o If there is no PARENT_WINDOW environment variable, the application
        should open top_level window in the root of the display.

Rationale:

    The assumption that a window manager controls the entire screen is
    not always appropriate.  An example is the debugging of a new
    window manager -- a working window manager might control the entire
    screen, while the new window manager that is being tested operates
    within one of its windows.  We need a way to arrange for
    applications to create their top-level windows not in the root, but
    in the window that is being managed by the window manager being
    tested.


Ellis Cohen
Siemens RTL Tiled Window Project
(609) 734-6524
ellis.cohen@a.gp.cs.cmu.edu