bsd/man/man2/ioctl.2

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