This variable has meaning only on graphical systems that create an application
window, such as Windows. Set this variable to "1" (on, true, yes) to indicate
that you've built your own user interface entirely in C or that you are using
an interface created by a code-generating tool. This is equivalent to
executing the runtime system with the "-b" command-line option. When this variable is
set to "1", the runtime won't create its own application window. Instead, your
C code must build its own window. When you provide your own user interface,
you may not use ACCEPT or DISPLAY verbs in your COBOL program (except for those
that don't interact with the screen or keyboard).
The default value is "0" (off, false, no).