usr/src/lib/libcurses/tstp.c

/*
 * Copyright (c) 1981 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)tstp.c      5.3 (Berkeley) %G%";
#endif /* not lint */

# include       <signal.h>

# include       "curses.ext"

/*
 * handle stop and start signals
 *
 * @(#)tstp.c   5.3 (Berkeley) %G%
 */
tstp() {

# ifdef SIGTSTP

        SGTTY   tty;
        int     omask;
# ifdef DEBUG
        if (outf)
                fflush(outf);
# endif
        tty = _tty;
        mvcur(0, COLS - 1, LINES - 1, 0);
        endwin();
        fflush(stdout);
        /* reset signal handler so kill below stops us */
        signal(SIGTSTP, SIG_DFL);
#define mask(s) (1 << ((s)-1))
        omask = sigsetmask(sigblock(0) &~ mask(SIGTSTP));
        kill(0, SIGTSTP);
        sigblock(mask(SIGTSTP));
        signal(SIGTSTP, tstp);
        _tty = tty;
        stty(_tty_ch, &_tty);
        wrefresh(curscr);
# endif SIGTSTP
}