xref: /freebsd-src/contrib/ncurses/progs/clear.c (revision aae38d10b4eebf81c0942947e8b83a9bb8651d88)
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28 
29 /****************************************************************************
30  *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
31  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
32  *     and: Thomas E. Dickey                        1996-on                 *
33  ****************************************************************************/
34 
35 /*
36  * clear.c --  clears the terminal's screen
37  */
38 
39 #define USE_LIBTINFO
40 #include <clear_cmd.h>
41 #include <tty_settings.h>
42 
43 MODULE_ID("$Id: clear.c,v 1.22 2017/10/07 21:48:32 tom Exp $")
44 
45 const char *_nc_progname = "clear";
46 
47 static void
48 usage(void)
49 {
50 #define KEEP(s) s "\n"
51     static const char msg[] =
52     {
53 	KEEP("")
54 	KEEP("Options:")
55 	KEEP("  -T TERM     use this instead of $TERM")
56 	KEEP("  -V          print curses-version")
57 	KEEP("  -x          do not try to clear scrollback")
58     };
59 #undef KEEP
60     (void) fprintf(stderr, "Usage: %s [options]\n", _nc_progname);
61     fputs(msg, stderr);
62     ExitProgram(EXIT_FAILURE);
63 }
64 
65 int
66 main(
67 	int argc GCC_UNUSED,
68 	char *argv[]GCC_UNUSED)
69 {
70     TTY tty_settings;
71     int fd;
72     int c;
73     char *term;
74     bool opt_x = FALSE;		/* clear scrollback if possible */
75 
76     _nc_progname = _nc_rootname(argv[0]);
77     term = getenv("TERM");
78 
79     while ((c = getopt(argc, argv, "T:Vx")) != -1) {
80 	switch (c) {
81 	case 'T':
82 	    use_env(FALSE);
83 	    use_tioctl(TRUE);
84 	    term = optarg;
85 	    break;
86 	case 'V':
87 	    puts(curses_version());
88 	    ExitProgram(EXIT_SUCCESS);
89 	case 'x':		/* do not try to clear scrollback */
90 	    opt_x = TRUE;
91 	    break;
92 	default:
93 	    usage();
94 	    /* NOTREACHED */
95 	}
96     }
97     if (optind < argc)
98 	usage();
99 
100     fd = save_tty_settings(&tty_settings, FALSE);
101 
102     setupterm(term, fd, (int *) 0);
103 
104     ExitProgram((clear_cmd(opt_x) == ERR)
105 		? EXIT_FAILURE
106 		: EXIT_SUCCESS);
107 }
108