examples/loadables/tty.c

   1 /* tty - return terminal name */
   2
   3 /* See Makefile for compilation details. */
   4
   5 /*
   6    Copyright (C) 1999-2009 Free Software Foundation, Inc.
   7
   8    This file is part of GNU Bash.
   9    Bash is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bash is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "config.h"
  24
  25 #include <stdio.h>
  26 #include "builtins.h"
  27 #include "shell.h"
  28 #include "bashgetopt.h"
  29 #include "common.h"
  30
  31 extern char *ttyname ();
  32
  33 tty_builtin (list)
  34      WORD_LIST *list;
  35 {
  36   int opt, sflag;
  37   char *t;
  38
  39   reset_internal_getopt ();
  40   sflag = 0;
  41   while ((opt = internal_getopt (list, "s")) != -1)
  42     {
  43       switch (opt)
  44         {
  45         case 's':
  46           sflag = 1;
  47           break;
  48         default:
  49           builtin_usage ();
  50           return (EX_USAGE);
  51         }
  52     }
  53   list = loptend;
  54
  55   t = ttyname (0);
  56   if (sflag == 0)
  57     puts (t ? t : "not a tty");
  58   return (t ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
  59 }
  60
  61 char *tty_doc[] = {
  62         "Display terminal name.",
  63         "",
  64         "tty writes the name of the terminal that is opened for standard",
  65         "input to standard output.  If the `-s' option is supplied, nothing",
  66         "is written; the exit status determines whether or not the standard",
  67         "input is connected to a tty.",
  68         (char *)NULL
  69 };
  70
  71 /* The standard structure describing a builtin command.  bash keeps an array
  72    of these structures. */
  73 struct builtin tty_struct = {
  74         "tty",                  /* builtin name */
  75         tty_builtin,            /* function implementing the builtin */
  76         BUILTIN_ENABLED,        /* initial flags for builtin */
  77         tty_doc,                /* array of long documentation strings. */
  78         "tty [-s]",             /* usage synopsis; becomes short_doc */
  79         0                       /* reserved for internal use */
  80 };