'more' doesn't understand 'xn' type terminals (such as 'xterm')

[Donn Seeley]

Subject: 'more' doesn't understand 'xn' type terminals (such as 'xterm')
Index:	ucb/more/more.c 4.3BSD

Description:
	When you run 'more' on a terminal which has the 'eat newline'
	feature described by the 'xn' termcap capability, it can screw
	up and lose blank lines.

Repeat-By:
	Go to a terminal with the 'eat newline' feature; it's easy to
	see the problem when you use a window created by the 'xterm'
	terminal emulator of the X window system.  Run the C-shell
	command:

		% (repeat 80 -n echo a; repeat 2 echo '') | more

	(Substitute the appropriate screen width for '80' if you use
	something different.) Run the same command on a normal terminal
	and compare -- 'more' on the 'eat newline' terminal will lose
	the blank line.

Fix:
	'more' has no code to handle 'xn' terminals, but it's easy to
	add.  Make the following changes to 'more.c', in the
	declarations at the top and in the routines getline() and
	initterm():

	------------------------------------------------------------
	*** /tmp/,RCSt1024200	Sun Jul 27 02:52:05 1986
	--- more.c	Sun Jul 27 02:14:23 1986
	***************
	*** 76,82 ****
	  int		inwait, Pause, errors;
	  int		within;	/* true if we are within a file,
				false if we are between files */
	! int		hard, dumb, noscroll, hardtabs, clreol;
	  int		catch_susp;	/* We should catch the SIGTSTP signal */
	  char		**fnames;	/* The list of file names */
	  int		nfiles;		/* Number of files left to process */
	--- 76,82 ----
	  int		inwait, Pause, errors;
	  int		within;	/* true if we are within a file,
				false if we are between files */
	! int		hard, dumb, noscroll, hardtabs, clreol, eatnl;
	  int		catch_susp;	/* We should catch the SIGTSTP signal */
	  char		**fnames;	/* The list of file names */
	  int		nfiles;		/* Number of files left to process */
	***************
	*** 768,773 ****
	--- 768,776 ----
		}
	      }
	      colflg = column == Mcol && fold_opt;
	+     if (colflg && eatnl && Wrap) {
	+ 	*p++ = '\n'; /* simulate normal wrap */
	+     }
	      *length = p - Line;
	      *p = 0;
	      return (column);
	***************
	*** 1494,1499 ****
	--- 1497,1504 ----
			hard++;	/* Hard copy terminal */
			Lpp = 24;
		    }
	+ 	    if (tgetflag("xn"))
	+ 		eatnl++; /* Eat newline at last column + 1; dec, concept */
		    if (Mcol <= 0)
			Mcol = 80;
	  
	------------------------------------------------------------

	Donn Seeley    University of Utah CS Dept    donn at utah-cs.arpa
	40 46' 6"N 111 50' 34"W    (801) 581-5668    decvax!utah-cs!donn