termios.html

unix 下的C开发手册,还用详细的例程。

not all values specified are required to be supported by 
the underlying hardware:
<pre>
<table  bordercolor=#000000 border=1 align=center><tr valign=top><th align=center><b>Mask Name</b>
<th align=center><b>Description</b>
<tr valign=top><td align=left>CLOCAL
<td align=left>Ignore modem status lines.
<tr valign=top><td align=left>CREAD
<td align=left>Enable receiver.
<tr valign=top><td align=left>CSIZE
<td align=left>Number of bits transmitted or received per byte:
<tr valign=top><td align=left>   CS5
<td align=left>   5 bits
<tr valign=top><td align=left>   CS6
<td align=left>   6 bits
<tr valign=top><td align=left>   CS7
<td align=left>   7 bits
<tr valign=top><td align=left>   CS8
<td align=left>   8 bits.
<tr valign=top><td align=left>CSTOPB
<td align=left>Send two stop bits, else one.
<tr valign=top><td align=left>HUPCL
<td align=left>Hang up on last close.
<tr valign=top><td align=left>PARENB
<td align=left>Parity enable.
<tr valign=top><td align=left>PARODD
<td align=left>Odd parity, else even.
</table>
</pre>
<p>
In addition, the input and output
baud rates are stored in the
<b>termios</b>
structure.
The following values are supported:
<pre>
<table  bordercolor=#000000 border=1 align=center><tr valign=top><th align=center><b>Name</b>
<th align=center><b>Description</b>
<th align=left>Name
<th align=center><b>Description</b>
<tr valign=top><td align=left>B0
<td align=left>Hang up
<td align=left>B600
<td align=left>600 baud
<tr valign=top><td align=left>B50
<td align=left>50 baud
<td align=left>B1200
<td align=left>1200 baud
<tr valign=top><td align=left>B75
<td align=left>75 baud
<td align=left>B1800
<td align=left>1800 baud
<tr valign=top><td align=left>B110
<td align=left>110 baud
<td align=left>B2400
<td align=left>2400 baud
<tr valign=top><td align=left>B134
<td align=left>134.5 baud
<td align=left>B4800
<td align=left>4800 baud
<tr valign=top><td align=left>B150
<td align=left>150 baud
<td align=left>B9600
<td align=left>9600 baud
<tr valign=top><td align=left>B200
<td align=left>200 baud
<td align=left>B19200
<td align=left>19200 baud
<tr valign=top><td align=left>B300
<td align=left>300 baud
<td align=left>B38400
<td align=left>38400 baud
</table>
</pre>
<p>
The following interfaces are provided for
getting and setting the values of the input and
output baud rates in the 
<b>termios</b>
structure:
<i><a href="../xsh/cfgetispeed.html">cfgetispeed()</a></i>,
<i><a href="../xsh/cfgetospeed.html">cfgetospeed()</a></i>,
<i><a href="../xsh/cfsetispeed.html">cfsetispeed()</a></i>
and
<i><a href="../xsh/cfsetospeed.html">cfsetospeed()</a></i>.
The effects on the terminal device do not become effective 
and not all errors are detected until the
<i><a href="../xsh/tcsetattr.html">tcsetattr()</a></i>
function is successfully called.
<br>
<p>
The CSIZE bits specify the number of transmitted or received bits
per byte.
If ISTRIP is not set, the value of all the other bits is
unspecified.
If ISTRIP is set, the value of
all but the 7 low-order bits is zero,
but the value of any other bits beyond CSIZE is unspecified when read.
CSIZE does not include the
parity bit, if any.
If CSTOPB is set, two stop bits are used,
otherwise one stop bit.
For example,
at 110 baud, two stop bits are normally used.
<p>
If CREAD is set, the receiver
is enabled.
Otherwise, no characters will be received.
<p>
If PARENB is set, parity generation
and detection is enabled and a parity bit is added to
each byte.
If parity is enabled,
PARODD specifies odd parity if set, otherwise even
parity is used.
<p>
If HUPCL is set, the modem
control lines for the port are lowered when the last
process with the port open closes
the port or the process terminates.
The modem
connection is broken.
<p>
If CLOCAL is set, a connection
does not depend on the state of the modem status lines.
If
CLOCAL is clear, the modem status
lines are monitored.
<p>
Under normal circumstances, a call to
the
<i><a href="../xsh/open.html">open()</a></i>
function waits for the modem connection to complete.
However, if the O_NONBLOCK flag is set (see
<i><a href="../xsh/open.html">open()</a></i>)
or if CLOCAL has been set, the
<i><a href="../xsh/open.html">open()</a></i>
function returns immediately without waiting for the connection.
<p>
If the object for which the
control modes are set is not an asynchronous serial connection,
some of the modes may be
ignored; for example, if an attempt is made to set the baud rate on a
network connection to a terminal on
another host, the baud rate may or may not be set on
the connection between that terminal and
the machine to which it is directly connected.
<p>
The initial hardware control value after
<i><a href="../xsh/open.html">open()</a></i>
is implementation-dependent.
<br>
<h4><a name = "tag_008_002_005">&nbsp;</a>Local Modes</h4>
<xref type="3" name="localmodes"></xref>
The
<b>c_lflag</b>
field of the argument
structure is used to control various functions.
It is composed of the
bitwise inclusive OR of the masks shown, which will be
bitwise distinct.
The mask name symbols in this table are defined
in
<i><a href="../xsh/termios.h.html">&lt;termios.h&gt;</a></i>;
not all values specified
are required to be supported by
the underlying hardware:
<p><table  bordercolor=#000000 border=1 align=center><tr valign=top><th align=center><b>Mask Name</b>
<th align=center><b>Description</b>
<tr valign=top><td align=left>ECHO
<td align=left>Enable echo.
<tr valign=top><td align=left>ECHOE
<td align=left>Echo ERASE as an error correcting backspace.
<tr valign=top><td align=left>ECHOK
<td align=left>Echo KILL.
<tr valign=top><td align=left>ECHONL
<td align=left>Echo &lt;newline&gt;.
<tr valign=top><td align=left>ICANON
<td align=left>Canonical input (erase and kill processing).
<tr valign=top><td align=left>IEXTEN
<td align=left>Enable extended (implementation-dependent) functions.
<tr valign=top><td align=left>ISIG
<td align=left>Enable signals.
<tr valign=top><td align=left>NOFLSH
<td align=left>Disable flush after interrupt, quit or suspend.
<tr valign=top><td align=left>TOSTOP
<td align=left>Send SIGTTOU for background output.
<tr valign=top><td align=left>XCASE
<td align=left> Canonical upper/lower presentation. (<b>LEGACY</b>)  
</table>
<p>
If ECHO is set, input characters are echoed back to the terminal.
If ECHO is clear, input characters are not echoed.
<p>
If ECHOE and ICANON are set,
the ERASE character causes the terminal to erase, if possible, the
last character in the current line from the display.
If there were no character to erase, an implementation might
echo an indication that this was the case, or do nothing.
<p>
If ECHOK and ICANON are set,
the KILL character causes the terminal to erase
the line from the display or echoes the newline
character after the KILL character.
<p>
If ECHONL and ICANON are set, the newline
character is echoed even if ECHO is not set.
<p>
If ICANON is set, canonical processing is enabled.
This enables the erase and kill edit
functions, and the assembly of input
characters into lines delimited by NL, EOF and
EOL, as described in
<xref href=canon><a href="#tag_008_001_006">
Canonical Mode Input Processing
</a></xref>.
<p>
If ICANON is not set, read
requests are satisfied directly from the input queue.
A read is not satisfied until at
least MIN bytes have been received or the timeout value
TIME expired between bytes.
The time value represents tenths of a second.
See
<xref href=noncanon><a href="#tag_008_001_007">
Non-canonical Mode Input Processing
</a></xref>
for more details.
<p>
If IEXTEN is set, implementation-dependent functions
are recognised from the input data.
It is implementation-dependent how IEXTEN
being set interacts with ICANON, ISIG, IXON or IXOFF.
If IEXTEN is not set, implementation-dependent functions are not
recognised and the corresponding input
characters are processed as described for
ICANON, ISIG, IXON and IXOFF.
<p>
If ISIG is set, each input character
is checked against the special control characters INTR,
QUIT and SUSP.
If an input character matches one of these control
characters, the function associated with that
character is performed.
If ISIG is not set, no checking is done.
Thus these special input functions are possible only if ISIG is set.
<p>
If NOFLSH is set, the normal
flush of the input and output queues associated with the
INTR, QUIT and SUSP characters is not done.
<p>
If TOSTOP is set, the signal SIGTTOU is sent
to the process group of a
process that tries to write to its controlling terminal if it is not in
the foreground process group for that terminal.
This signal, by default, stops the members of the process group.
Otherwise, the output generated by that process is output
to the current output stream.
Processes that are blocking or ignoring SIGTTOU signals
are excepted and allowed to produce
output, and the SIGTTOU signal is not sent.
<p>
If XCASE is set, canonical lower and
canonical upper presentation are performed.
In locales other than the POSIX locale, the effect is unspecified.
(<b>LEGACY</b>)
<p>
The initial local control value after
<i><a href="../xsh/open.html">open()</a></i>
is implementation-dependent.
<br>
<h4><a name = "tag_008_002_006">&nbsp;</a>Special Control Characters</h4>
The special control characters values are
defined by the array
<b>c_cc</b>.
The subscript name
and description for each element in
both canonical and non-canonical modes are as
follows:
<p><table  bordercolor=#000000 border=1 align=center><tr valign=top><th colspan=2 align=center><b>Subscript Usage</b>
<th align=left>&nbsp;
<tr valign=top><th align=center><b>Canonical</b>
<th align=center><b>Non-canonical</b>
<th align=left>&nbsp;
<tr valign=top><th align=center><b>Mode</b>
<th align=center><b>Mode</b>
<th align=center><b>Description</b>
<tr valign=top><td align=left>VEOF
<td align=left>&nbsp;
<td align=left>EOF character
<tr valign=top><td align=left>VEOL
<td align=left>&nbsp;
<td align=left>EOL character
<tr valign=top><td align=left>VERASE
<td align=left>&nbsp;
<td align=left>ERASE character
<tr valign=top><td align=left>VINTR
<td align=left>VINTR
<td align=left>INTR character
<tr valign=top><td align=left>VKILL
<td align=left>&nbsp;
<td align=left>KILL character
<tr valign=top><td align=left>&nbsp;
<td align=left>VMIN
<td align=left>MIN value
<tr valign=top><td align=left>VQUIT
<td align=left>VQUIT
<td align=left>QUIT character
<tr valign=top><td align=left>VSUSP
<td align=left>VSUSP
<td align=left>SUSP character
<tr valign=top><td align=left>&nbsp;
<td align=left>VTIME
<td align=left>TIME value
<tr valign=top><td align=left>VSTART
<td align=left>VSTART
<td align=left>START character
<tr valign=top><td align=left>VSTOP
<td align=left>VSTOP
<td align=left>STOP character
</table>
<p>
The subscript values are unique,
except that the VMIN and VTIME subscripts may
have the same values as the
VEOF and VEOL subscripts, respectively.
<p>
The number of elements in the
<b>c_cc</b>
array, NCCS, is unspecified.
<p>
Implementations that do not support changing the START and STOP
characters may ignore the character values in the
<b>c_cc</b>
array indexed by the VSTART and VSTOP subscripts when
<i><a href="../xsh/tcsetattr.html">tcsetattr()</a></i>
is called, but will return the value in use when
<i><a href="../xsh/tcgetattr.html">tcgetattr()</a></i>
is called.
<p>
The initial values of all control
characters are implementation-dependent.
<p>
If the value of one of
the changeable special control characters (see
<xref href=specchar><a href="#tag_008_001_009">
Special Characters
</a></xref>)
is {_POSIX_VDISABLE}, that function is disabled; 
that is, no input data will be recognised as the disabled special character.
If ICANON is not set, the value of {_POSIX_VDISABLE} has no special
meaning for the VMIN and VTIME entries of the
<b>c_cc</b>
array.

</blockquote>
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