man3/getttyent.3

   1 .\"  Copyright 2002 walter harms (walter.harms@informatik.uni-oldenburg.de)
   2 .\"
   3 .\" SPDX-License-Identifier: GPL-1.0-or-later
   4 .\"
   5 .TH GETTTYENT 3 2021-03-22 "Linux man-pages (unreleased)" "Linux Programmer's Manual"
   6 .SH NAME
   7 getttyent, getttynam, setttyent, endttyent \- get ttys file entry
   8 .SH LIBRARY
   9 Standard C library
  10 .RI ( libc ", " \-lc )
  11 .SH SYNOPSIS
  12 .nf
  13 .B "#include <ttyent.h>"
  14 .PP
  15 .B "struct ttyent *getttyent(void);"
  16 .BI "struct ttyent *getttynam(const char *" name );
  17 .PP
  18 .B "int setttyent(void);"
  19 .B "int endttyent(void);"
  20 .fi
  21 .SH DESCRIPTION
  22 These functions provide an interface to the file
  23 .B _PATH_TTYS
  24 (e.g.,
  25 .IR /etc/ttys ).
  26 .PP
  27 The function
  28 .BR setttyent ()
  29 opens the file or rewinds it if already open.
  30 .PP
  31 The function
  32 .BR endttyent ()
  33 closes the file.
  34 .PP
  35 The function
  36 .BR getttynam ()
  37 searches for a given terminal name in the file.
  38 It returns a pointer to a
  39 .I ttyent
  40 structure (description below).
  41 .PP
  42 The function
  43 .BR getttyent ()
  44 opens the file
  45 .B _PATH_TTYS
  46 (if necessary) and returns the first entry.
  47 If the file is already open, the next entry.
  48 The
  49 .I ttyent
  50 structure has the form:
  51 .PP
  52 .in +4n
  53 .EX
  54 struct ttyent {
  55     char *ty_name;     /* terminal device name */
  56     char *ty_getty;    /* command to execute, usually getty */
  57     char *ty_type;     /* terminal type for termcap */
  58     int   ty_status;   /* status flags */
  59     char *ty_window;   /* command to start up window manager */
  60     char *ty_comment;  /* comment field */
  61 };
  62 .EE
  63 .in
  64 .PP
  65 .I ty_status
  66 can be:
  67 .PP
  68 .in +4n
  69 .EX
  70 #define TTY_ON     0x01  /* enable logins (start ty_getty program) */
  71 #define TTY_SECURE 0x02  /* allow UID 0 to login */
  72 .EE
  73 .in
  74 .SH ATTRIBUTES
  75 For an explanation of the terms used in this section, see
  76 .BR attributes (7).
  77 .ad l
  78 .nh
  79 .TS
  80 allbox;
  81 lbx lb lb
  82 l l l.
  83 Interface       Attribute       Value
  84 T{
  85 .BR getttyent (),
  86 .BR setttyent (),
  87 .BR endttyent (),
  88 .BR getttynam ()
  89 T}      Thread safety   MT-Unsafe race:ttyent
  90 .TE
  91 .hy
  92 .ad
  93 .sp 1
  94 .SH STANDARDS
  95 Not in POSIX.1.
  96 Present on the BSDs, and perhaps other systems.
  97 .SH NOTES
  98 Under Linux, the file
  99 .IR /etc/ttys ,
 100 and the functions described above, are not used.
 101 .SH SEE ALSO
 102 .BR ttyname (3),
 103 .BR ttyslot (3)