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From: guy@gorodish.UUCP
Newsgroups: comp.bugs.4bsd
Subject: "overwrite" in -lcurses drops core
Message-ID: <15585@sun.uucp>
Date: Tue, 24-Mar-87 23:12:17 EST
Article-I.D.: sun.15585
Posted: Tue Mar 24 23:12:17 1987
Date-Received: Fri, 27-Mar-87 00:45:30 EST
Sender: news@sun.uucp
Lines: 61

Index:	usr.lib/libcurses/overwrite.c 4.3BSD

Description:
	"overwrite" can drop core in some circumstances.
Repeat-By:
	Run the following program:

# include <curses.h>

char junk[] = "junk";
char morjunk[] = "MORE JUNK";

main()
{
	WINDOW	*win, *swin, *twin;
	int	i, j;

	initscr ();
	noecho();
	crmode();
	twin = newwin(LINES,COLS,0,0);
	wclear(twin);
	for(i = 0; i < LINES - 1; i++)
	  for(j = 0; j < COLS - 1; j++)
		mvwaddch(twin, i, j, 'A' + i);
	wrefresh (twin);
	getch();
	win = newwin(LINES/2, COLS/2, 0, COLS/2);
	swin = subwin(win, LINES/2-1, COLS/2-1, 1, COLS/2+1);
	overwrite(twin, swin);
	for(i = 1; i < LINES/2-2; i++)
	 for(j = 1; j < COLS/2-2; j++)
	  mvwaddch(win, i, j, morjunk[j % (sizeof(morjunk)-1)]);
	touchwin(win);
	wrefresh(win);
	getch();
	endwin();
}

	It will paint the screen and stop.  When it stops, hit RETURN
	and watch it drop core.
Fix:
*** /arch/4.3/usr/src/usr.lib/libcurses/overwrite.c	Fri Jun  7 11:39:28 1985
--- overwrite.c	Tue Mar 24 20:05:06 1987
***************
*** 29,35 ****
  # endif
  	starty = max(win1->_begy, win2->_begy);
  	startx = max(win1->_begx, win2->_begx);
! 	endy = min(win1->_maxy + win1->_begy, win2->_maxy + win2->_begx);
  	endx = min(win1->_maxx + win1->_begx, win2->_maxx + win2->_begx);
  	if (starty >= endy || startx >= endx)
  		return;
--- 29,35 ----
  # endif
  	starty = max(win1->_begy, win2->_begy);
  	startx = max(win1->_begx, win2->_begx);
! 	endy = min(win1->_maxy + win1->_begy, win2->_maxy + win2->_begy);
  	endx = min(win1->_maxx + win1->_begx, win2->_maxx + win2->_begx);
  	if (starty >= endy || startx >= endx)
  		return;