Path: utzoo!attcan!uunet!mcvax!enea!zyx!arndt From: arndt@zyx.SE (Arndt Jonasson) Newsgroups: comp.unix.questions Subject: Undefined erase/kill characters? Message-ID: <2652@zyx.SE> Date: 5 Jul 88 13:25:07 GMT Reply-To: arndt@zyx.SE (Arndt Jonasson) Organization: ZYX Sweden AB, Stockholm, Sweden Lines: 24 The characters to use for erasing a single character and erasing an entire line, commonly called 'erase' and 'kill' and readble/settable by the 'stty' command, are stored in a character array pertaining to the terminal driver, which is updated and read by the 'ioctl' requests TCGETA/TCSETA/TCSETAF (in SysV) or TIOCGETP/TIOCSETN/TIOCSETP (in BSD). My question is: can any character (from 0 to 255) be made to, say, 'erase', or is there some value which indicates "undefined"? I have looked in the Gnu Emacs source code and it uses the symbol CDEL (which is #define'd to 0377 inon my system) to mean undefined. In HP-UX, however, that value is treated as any other, i.e. Delete with parity erases the last character. What do Unix systems normally do? Is there a standard for this (meaning common usage, rather than prescription)? Do the SVID/SVVS bother to specify this? A related question: what is supposed to happen when more than one characters in this array are set to the same value? Which function is used when the terminal driver sees the character? -- Arndt Jonasson, ZYX Sweden AB, Styrmansgatan 6, 114 54 Stockholm, Sweden email address: arndt@zyx.SE or !mcvax!enea!zyx!arndt