Close - causes the named window to be closed. If the name is omitted, all currently open windows are closed. This is the default. A window environment is created that is independent of the background and any other window. Initially, the new window environment is inherited from and identical to the background environment.
New windows are created empty, that is, they contain no fields.
The contents of the current window may be defined or modified by calling the Attribute , Cursor , Format , Options , and Xlist functions. For ease of description, let the environment be represented by a single option, say the FILL character. The OPEN option will make an existing window current without modifying the content of the window. The window may then be reformatted at the new location. For clarity, this documentation has portrayed a window as a rectangular subsection of a visual display.