Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cpqhou!pipkinsj From: pipkinsj@cpqhou.uucp (Jeff Pipkins @Adv Dev@SE hou ) Newsgroups: comp.lang.postscript Subject: Re: Postscript printing small and mirrorimaged!! Message-ID: <1991Jan07.165702.26015@cpqhou.uucp> Date: 7 Jan 91 16:57:02 GMT References: <1196@vidiot.UUCP> <1991Jan04.173636.9674@cpqhou.uucp> <1208@vidiot.UUCP> <1991Jan6.010757.3151@ni.umd.edu> Reply-To: pipkinsj@cpqhou.UUCP (Jeff Pipkins @Adv Dev@SE hou ) Organization: Compaq Computer Corporation Lines: 38 The question I responded to specified a parallel interface. Ctrl-D's are only for parallel and serial interfaces, and as many of you have pointed out, have no place in network sessions such as Appletalk, Ethernet, or whatevernet. It is true that the Ctrl-D character is not part of the PostScript language itself. The PostScript language has no convention for marking the end of a job! If you are connected to a network, then finding the end of the job is no problem, since the protocol implies that information (end of file == end of job). If you are connected to serial or parallel, then the printer itself (or other graphics device) needs to know when the job ends. All Adobe PostScript implementations on every device I have ever heard of use the Ctrl-D to mark the end of the job on parallel or serial channels. This does not mean that it's part of the language -- but it seems to be a part of Adobe's implementation of the PostScript language. In reference to what actually happens: before running a job, the PostScript interpreter's "server loop" does a "save". When PostScript gets a Ctrl-D (over the parallel or serial port) it does a "restore" (thereby reclaiming VM) and then another "save" for the next job. That's why you have to exit the server loop to make changes that persist from job to job. BTW, the Ctrl-C character (over parallel or serial) "cancels" the current job, but I'm not completely sure what is meant by that, nor whether it is implemented the same in all cases. On the serial channel only, you can send a Ctrl-T and it will send a short status string back. This is also clearly not part of the PostScript language, but it is there in most implementations. Well, there's the can of worms. Everybody dig in... -- Jeff D. Pipkins (uunet!cpqhou!pipkinsj) My disclaimer: My opinions do not necessarily reflect those of my employer. Papaw's disclaimer: I've already told you more than I know.