bsd/man/man2/ioctl.2

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  34 .\"     @(#)ioctl.2     8.2 (Berkeley) 12/11/93
  35 .\"
  36 .Dd December 11, 1993
  37 .Dt IOCTL 2
  38 .Os BSD 4
  39 .Sh NAME
  40 .Nm ioctl
  41 .Nd control device
  42 .Sh SYNOPSIS
  43 .Fd #include <sys/ioctl.h>
  44 .Ft int
  45 .Fo ioctl
  46 .Fa "int fildes"
  47 .Fa "unsigned long request"
  48 .Fa "..."
  49 .Fc
  50 .Sh DESCRIPTION
  51 The
  52 .Fn ioctl
  53 function manipulates the underlying device parameters of special files.
  54 In particular, many operating
  55 characteristics of character special files (e.g. terminals)
  56 may be controlled with
  57 .Fn ioctl
  58 requests.
  59 The argument
  60 .Fa fildes
  61 must be an open file descriptor.
  62 .Pp
  63 An  ioctl
  64 .Fa request
  65 has encoded in it whether the argument is an
  66 .Dq in
  67 parameter
  68 or
  69 .Dq out
  70 parameter, and the size of the argument
  71 .Fa argp
  72 in bytes.
  73 Macros and defines used in specifying an ioctl
  74 .Fa request
  75 are located in the file
  76 .Ao Pa sys/ioctl.h Ac .
  77 .Sh RETURN VALUES
  78 If an error has occurred, a value of -1 is returned and
  79 .Va errno
  80 is set to indicate the error.
  81 .Sh ERRORS
  82 .Fn Ioctl
  83 will fail if:
  84 .Bl -tag -width Er
  85 .\" ==========
  86 .It Bq Er EBADF
  87 .Fa fildes
  88 is not a valid descriptor.
  89 .\" ==========
  90 .It Bq Er EINVAL
  91 .Fa Request
  92 or
  93 .Fa argp
  94 is not valid.
  95 .\" ==========
  96 .It Bq Er ENOTTY
  97 .Fa fildes
  98 is not associated with a character
  99 special device.
 100 .\" ==========
 101 .It Bq Er ENOTTY
 102 The specified request does not apply to the kind
 103 of object that the descriptor
 104 .Fa fildes
 105 references.
 106 .El
 107 .Sh SEE ALSO
 108 .Xr cdio 1 ,
 109 .Xr chio 1 ,
 110 .Xr mt 1 ,
 111 .Xr execve 2 ,
 112 .Xr fcntl 2 ,
 113 .Xr intro 4 ,
 114 .Xr tty 4
 115 .Sh HISTORY
 116 An
 117 .Fn ioctl
 118 function call appeared in
 119 .At v7 .