diplodocus.org Git - nmh/blob - docs/historical/mh-jun-1982/Extras/libg/ttynam.c

   1 #ifdef COMMENT
   2         Proprietary Rand Corporation, 1981.
   3         Further distribution of this software
   4         subject to the terms of the Rand
   5         license agreement.
   6 #endif
   7
   8 #include "libg.h"
   9
  10 /* this routine returns the file name within "/dev" */
  11 /* corresponding to the internal tty #, which */
  12 /* is in turn used by ttynum and getwho */
  13 /* this routine is obviously very system dependent. */
  14
  15 /* ttyname is set up so that, in conjunction */
  16 /* with getwho, the following simple "who" program will work: */
  17 /* for (i = 0; ttnam = ttyname(i); i++)    */
  18 /*     if (luid = getwho(i)) printf("%s %s\n",ttnam,getlogn(luid)); */
  19
  20 /* also, ttynum(ttyname(n)) should equal n if 0 <= n <= 31 */
  21
  22 char *ttyname(num)
  23 {
  24         register char *tty;
  25         tty = "ttyx";
  26         if (num < 0 || num > 31) return(NULSTR);
  27         if (num == 0) return("tty8");
  28         if (num < 9) {
  29                 tty[3] = num + ('0' - 1);
  30                 return(tty);
  31         }
  32         tty[3] = num - ('a' - 9);
  33         return(tty);
  34 }