Path: utzoo!attcan!uunet!lll-winken!lll-ncis!helios.ee.lbl.gov!pasteur!ucbvax!ulysses!cjc
From: cjc@ulysses.homer.nj.att.com (Chris Calabrese[mav])
Newsgroups: comp.windows.news
Subject: Re: retained canvases - application writers please read
Summary: null parent canvases
Message-ID: <11090@ulysses.homer.nj.att.com>
Date: 12 Jan 89 15:11:55 GMT
References: <24631@sgi.SGI.COM> <1154@murtoa.cs.mu.oz.au>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 24

In article <1154@murtoa.cs.mu.oz.au>, mwp@murtoa (Michael Paddon) writes:
| [...]
| To quote the NeWS 1.1 "READ THIS FIRST" document, Page 8
| 
| 	"One exception to this rule (that the NeWS server may ignore
| 	retained hints) is that the NeWS server must honor the
| 	/Retained setting of parent-less canvases"
| 
| I presume that a parent-less canvas is one with a null value in
| its /Parent entry, although this is not explicitly stated. Note
| that any canvas may be made parent-less at any time.
| [...]

I just tried changing `framebuffer' to a `null' in one
of my program segments (to draw a window), and got:

Process: 0x81B630   Error: typecheck
Stack: ... /FrameCanvas null
Executing: `newcanvas'
At: {/FrameCanvas ParentCanvas *`newcanvas' 'def' /beye
/beye_m FrameCanvas setstandardcursor FrameCanvas /SaveBehind 'true' 'put'}
In: {*CreateFrameCanvas CreateClientCanvas CreateIconCanvas
CreateFrameControls CreateFrameInterests CreateFrameMenu
CreateIconControls CreateIconInterests CreateIconMenu ShapeIconCanvas}