gen/tcsendbreak.3

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  32 .\"     @(#)tcsendbreak.3       8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/tcsendbreak.3,v 1.8 2001/10/01 16:08:51 ru Exp $
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  35 .Dd June 4, 1993
  36 .Dt TCSENDBREAK 3
  37 .Os
  38 .Sh NAME
  39 .Nm tcdrain ,
  40 .Nm tcflow ,
  41 .Nm tcflush ,
  42 .Nm tcsendbreak
  43 .Nd line control functions
  44 .Sh LIBRARY
  45 .Lb libc
  46 .Sh SYNOPSIS
  47 .In termios.h
  48 .Ft int
  49 .Fo tcdrain
  50 .Fa "int fildes"
  51 .Fc
  52 .Ft int
  53 .Fo tcflow
  54 .Fa "int fildes"
  55 .Fa "int action"
  56 .Fc
  57 .Ft int
  58 .Fo tcflush
  59 .Fa "int fildes"
  60 .Fa "int action"
  61 .Fc
  62 .Ft int
  63 .Fo tcsendbreak
  64 .Fa "int fildes"
  65 .Fa "int duration"
  66 .Fc
  67 .Sh DESCRIPTION
  68 The
  69 .Fn tcdrain
  70 function waits until all output written to the terminal referenced by
  71 .Fa fildes
  72 has been transmitted to the terminal.
  73 .Pp
  74 The
  75 .Fn tcflow
  76 function suspends transmission of data to,
  77 or the reception of data from,
  78 the terminal referenced by
  79 .Fa fildes ,
  80 depending on the value of
  81 .Fa action .
  82 The value of
  83 .Fa action
  84 must be one of the following:
  85 .Bl -tag -width "TCIOFF"
  86 .It Fa TCOOFF
  87 Suspend output.
  88 .It Fa TCOON
  89 Restart suspended output.
  90 .It Fa TCIOFF
  91 Transmit a STOP character, which is intended to cause the terminal to stop
  92 transmitting data to the system.
  93 (See the description of IXOFF in the
  94 .Ql Input Modes
  95 section of
  96 .Xr termios 4 ) .
  97 .It Fa TCION
  98 Transmit a START character, which is intended to cause the terminal to start
  99 transmitting data to the system.
 100 (See the description of IXOFF in the
 101 .Ql Input Modes
 102 section of
 103 .Xr termios 4 ) .
 104 .El
 105 .Pp
 106 The
 107 .Fn tcflush
 108 function discards any data written to the terminal referenced by
 109 .Fa fildes
 110 which has not been transmitted to the terminal, or any data received
 111 from the terminal but not yet read, depending on the value of
 112 .Fa action .
 113 The value of
 114 .Fa action
 115 must be one of the following:
 116 .Bl -tag -width "TCIOFLUSH"
 117 .It Fa TCIFLUSH
 118 Flush data received but not read.
 119 .It Fa TCOFLUSH
 120 Flush data written but not transmitted.
 121 .It Fa TCIOFLUSH
 122 Flush both data received but not read and data written but not transmitted.
 123 .El
 124 .Pp
 125 The
 126 .Fn tcsendbreak
 127 function transmits a continuous stream of zero-valued bits for four-tenths
 128 of a second to the terminal referenced by
 129 .Fa fildes .
 130 The
 131 .Fa duration
 132 parameter is ignored in this implementation.
 133 .Sh RETURN VALUES
 134 Upon successful completion, all of these functions return a value of zero.
 135 .Sh ERRORS
 136 If any error occurs, a value of -1 is returned and the global variable
 137 .Va errno
 138 is set to indicate the error, as follows:
 139 .Bl -tag -width Er
 140 .It Bq Er EBADF
 141 The
 142 .Fa fildes
 143 argument is not a valid file descriptor.
 144 .It Bq Er EINTR
 145 A signal interrupted the
 146 .Fn tcdrain
 147 function.
 148 .It Bq Er EINVAL
 149 The
 150 .Fa action
 151 argument is not a proper value.
 152 .It Bq Er ENOTTY
 153 The file associated with
 154 .Fa fildes
 155 is not a terminal.
 156 .El
 157 .Sh SEE ALSO
 158 .Xr tcsetattr 3 ,
 159 .Xr termios 4
 160 .Sh STANDARDS
 161 The
 162 .Fn tcsendbreak ,
 163 .Fn tcdrain ,
 164 .Fn tcflush
 165 and
 166 .Fn tcflow
 167 functions are expected to be compliant with the
 168 .St -p1003.1-88
 169 specification.