examples/loadables/tty.c

   1 /* tty - return terminal name */
   2
   3 /* See Makefile for compilation details. */
   4
   5 #include "config.h"
   6
   7 #include <stdio.h>
   8 #include "builtins.h"
   9 #include "shell.h"
  10 #include "bashgetopt.h"
  11
  12 extern char *ttyname ();
  13
  14 tty_builtin (list)
  15      WORD_LIST *list;
  16 {
  17   int opt, sflag;
  18   char *t;
  19
  20   reset_internal_getopt ();
  21   sflag = 0;
  22   while ((opt = internal_getopt (list, "s")) != -1)
  23     {
  24       switch (opt)
  25         {
  26         case 's':
  27           sflag = 1;
  28           break;
  29         default:
  30           builtin_usage ();
  31           return (EX_USAGE);
  32         }
  33     }
  34   list = loptend;
  35
  36   t = ttyname (0);
  37   if (sflag == 0)
  38     puts (t ? t : "not a tty");
  39   return (t ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
  40 }
  41
  42 char *tty_doc[] = {
  43         "tty writes the name of the terminal that is opened for standard",
  44         "input to standard output.  If the `-s' option is supplied, nothing",
  45         "is written; the exit status determines whether or not the standard",
  46         "input is connected to a tty.",
  47         (char *)NULL
  48 };
  49
  50 /* The standard structure describing a builtin command.  bash keeps an array
  51    of these structures. */
  52 struct builtin tty_struct = {
  53         "tty",                  /* builtin name */
  54         tty_builtin,            /* function implementing the builtin */
  55         BUILTIN_ENABLED,        /* initial flags for builtin */
  56         tty_doc,                /* array of long documentation strings. */
  57         "tty [-s]",             /* usage synopsis; becomes short_doc */
  58         0                       /* reserved for internal use */
  59 };