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<H1>termio(7)</H1>
<HR>
<B>termio -- <!--Meta NM "termio"-->general terminal interface </B><!--Meta DN "general terminal interface"-->
<P>
<H2>Synopsis</H2><PRE>#include &lt;termio.h&gt;
<P>
ioctl(int <B><I>fildes</I></B>, int <B><I>request</I></B>, struct termio *<B><I>arg</I></B>);
ioctl(int <B><I>fildes</I></B>, int <B><I>request</I></B>, int <B><I>arg</I></B>);
<P>
#include &lt;termios.h&gt;
<P>
ioctl(int <B><I>fildes</I></B>, int <B><I>request</I></B>, struct termios *<B><I>arg</I></B>);
</P></PRE>
<H2>Description</H2>System V supports a general interface for asynchronous
communications ports that is hardware-independent. The user interface to this
functionality is via function calls (the preferred interface) described in <A
href="http://docsrv.caldera.com/cgi-bin/man/man?termios+3C"><B>termios</B>(3C)</A>
or <B>ioctl</B> commands described in this section. This section also discusses
the common features of the terminal subsystem which are relevant with both user
interfaces.
<P>When a terminal file is opened, it normally causes the process to wait until
a connection is established. In practice, users' programs seldom open terminal
files; they are opened by the system and become a user's standard input, output,
and error files. The very first terminal file opened by the session leader,
which is not already associated with a session, becomes the controlling terminal
for that session. The controlling terminal plays a special role in handling quit
and interrupt signals, as discussed below. The controlling terminal is inherited
by a child process during a <A
href="http://docsrv.caldera.com/cgi-bin/man/man?fork+2"><B>fork</B>(2)</A>. A
process can break this association by changing its session using <A
href="http://docsrv.caldera.com/cgi-bin/man/man?setsid+2"><B>setsid</B>(2)</A>.
<P>A terminal associated with one of these files ordinarily operates in
full-duplex mode. Characters may be typed at any time, even while output is
occurring, and are only lost when the character input buffers of the system
become completely full, which is rare (for example, if the number of characters
in the line discipline buffer exceeds <B>MAX_CANON</B> and <B>IMAXBEL</B> (see
below) is not set), or when the user has accumulated <B>MAX_INPUT</B> number of
input characters that have not yet been read by some program. When the input
limit is reached, all the characters saved in the buffer up to that point are
thrown away without notice.
<H3>Session management (Job control)</H3>A control terminal will distinguish one
of the process groups in the session associated with it to be the foreground
process group. All other process groups in the session are designated as
background process groups. This foreground process group plays a special role in
handling signal-generating input characters, as discussed below. By default,
when a controlling terminal is allocated, the controlling process's process
group is assigned as foreground process group.
<P>Background process groups in the controlling process's session are subject to
a job control line discipline when they attempt to access their controlling
terminal. Process groups can be sent signals that will cause them to stop,
unless they have made other arrangements. An exception is made for members of
orphaned process groups. These are process groups which do not have a member
with a parent in another process group that is in the same session and therefore
shares the same controlling terminal. When a member's orphaned process group
attempts to access its controlling terminal, errors will be returned, since
there is no process to continue it if it should stop.
<P>If a member of a background process group attempts to read its controlling
terminal, its process group will be sent a <B>SIGTTIN</B> signal, which will
normally cause the members of that process group to stop. If, however, the
process is ignoring or holding <B>SIGTTIN</B>, or is a member of an orphaned
process group, the read will fail with <B>errno</B> set to <B>EIO</B>, and no
signal will be sent.
<P>If a member of a background process group attempts to write its controlling
terminal and the <B>TOSTOP</B> bit is set in the <B><I>c_lflag</I></B> field,
its process group will be sent a <B>SIGTTOU</B> signal, which will normally
cause the members of that process group to stop. If, however, the process is
ignoring or holding <B>SIGTTOU</B>, the write will succeed. If the process is
not ignoring or holding <B>SIGTTOU</B> and is a member of an orphaned process
group, the write will fail with <B>errno</B> set to <B>EIO</B>, and no signal
will be sent.
<P>If <B>TOSTOP</B> is set and a member of a background process group attempts
to <B>ioctl</B> its controlling terminal, and that <B>ioctl</B> will modify
terminal parameters (for example, <B>TCSETA</B>, <B>TCSETAW</B>, <B>TCSETAF</B>,
or <B>TIOCSPGRP</B>), its process group will be sent a <B>SIGTTOU</B> signal,
which will normally cause the members of that process group to stop. If,
however, the process is ignoring or holding <B>SIGTTOU</B>, the ioctl will
succeed. If the process is not ignoring or holding <B>SIGTTOU</B> and is a
member of an orphaned process group, the write will fail with <B>errno</B> set
to <B>EIO</B>, and no signal will be sent.
<H3>Canonical mode input processing</H3>Normally, terminal input is processed in
units of lines. A line is delimited by a newline (ASCII <B>LF</B>) character, an
end-of-file (ASCII) <B>EOT</B> character, or an end-of-line character. This
means that a program attempting to read will be suspended until an entire line
has been typed. Also, no matter how many characters are requested in the read
call, at most one line will be returned. It is not necessary, however, to read a
whole line at once; any number of characters may be requested in a read, even
one, without losing information.
<P>During input, erase and kill processing is normally done. The <B>ERASE</B>
character (by default, the character <B>BS</B>) erases the last character typed.
The <B>WERASE</B> character (&lt;Ctrl&gt;<B>W</B>) erases the last ``word''
typed in the current input line (but not any preceding spaces or tabs). A
``word'' is defined as a sequence of non-blank characters, with tabs counted as
blanks. Neither <B>ERASE</B> nor <B>WERASE</B> will erase beyond the beginning
of the line. The <B>KILL</B> character (by default, the character <B>NAK</B>)
kills (deletes) the entire input line, and optionally outputs a newline
character. All these characters operate on a key stroke basis, independent of
any backspacing or tabbing that may have been done. The <B>REPRINT</B> character
(&lt;Ctrl&gt;<B>R</B>) prints a newline followed by all characters that have not
been read. Reprinting also occurs automatically if characters that would
normally be erased from the screen are fouled by program output. The characters
are reprinted as if they were being echoed; consequencely, if <B>ECHO</B> is not
set, they are not printed.
<P>The <B>ERASE</B> and <B>KILL</B> characters may be entered literally by
preceding them with the escape character (``\''). In this case, the escape
character is not read. The erase and kill characters may be changed.
<H3>Non-canonical mode input processing</H3>In non-canonical mode input
processing, input characters are not assembled into lines, and erase and kill
processing does not occur. The <B>MIN</B> and <B>TIME</B> values are used to
determine how to process the characters received.
<P><B>MIN</B> represents the minimum number of characters that should be
received when the read is satisfied (that is, when the characters are returned
to the user). <B>TIME</B> is a timer of 0.10-second granularity that is used to
timeout bursty and short-term data transmissions. The values for <B>MIN</B> and
<B>TIME</B> should be set by the programmer in the <B>termios</B> or
<B>termio</B> structure. The four possible values for <B>MIN</B> and <B>TIME</B>
and their interactions are described below.
<DL compact>
<P>
<DT>Case A: <B>MIN</B> &gt; 0, <B>TIME</B> &gt; 0
<DD>In this case, <B>TIME</B> serves as an intercharacter timer and is
activated after the first character is received. Since it is an intercharacter
timer, it is reset after a character is received. The interaction between
<B>MIN</B> and <B>TIME</B> is as follows: as soon as one character is
received, the intercharacter timer is started. If <B>MIN</B> characters are
received before the intercharacter timer expires (note that the timer is reset
upon receipt of each character), the read is satisfied. If the timer expires
before <B>MIN</B> characters are received, the characters received to that
point are returned to the user. Note that if <B>TIME</B> expires, at least one
character will be returned because the timer would not have been enabled
unless a character was received. In this case (<B>MIN</B> &gt; 0, <B>TIME</B>
&gt; 0), the read sleeps until the <B>MIN</B> and <B>TIME</B> mechanisms are
activated by the receipt of the first character. If the number of characters
read is less than the number of characters available, the timer is not
reactivated and the subsequent read is satisfied immediately.
<P></P>
<DT>Case B: <B>MIN</B> &gt; 0, <B>TIME</B> = 0
<DD>In this case, since the value of <B>TIME</B> is zero, the timer plays no
role and only <B>MIN</B> is significant. A pending read is not satisfied until
<B>MIN</B> characters are received (the pending read sleeps until <B>MIN</B>
characters are received). A program that uses this case to read record based
terminal <B>I/O</B> may block indefinitely in the read operation.
<P></P>
<DT>Case C: <B>MIN</B> = 0, <B>TIME</B> &gt; 0
<DD>In this case, since <B>MIN</B> = 0, <B>TIME</B> no longer represents an
intercharacter timer: it now serves as a read timer that is activated as soon
as a <B>read</B> is done. A read is satisfied as soon as a single character is
received or the read timer expires. Note that, in this case, if the timer
expires, no character is returned. If the timer does not expire, the only way
the read can be satisfied is if a character is received. In this case, the
read will not block indefinitely waiting for a character; if no character is
received within <B>TIME</B>*.10 seconds after the read is initiated, the read
returns with zero characters.
<P></P>
<DT>Case D: <B>MIN</B> = 0, <B>TIME</B> = 0
<DD>In this case, return is immediate. The minimum of either the number of
characters requested or the number of characters currently available is
returned without waiting for more characters to be input. </DD></DL>
<H3>Comparison of the different cases of MIN, TIME interaction</H3>Some points
to note about <B>MIN</B> and <B>TIME</B>:
<UL>
<P>
<LI>In the following explanations, note that the interactions of <B>MIN</B>
and <B>TIME</B> are not symmetric. For example, when <B>MIN</B> &gt; 0 and
<B>TIME</B> = 0, <B>TIME</B> has no effect. However, in the opposite case,
where <B>MIN</B> = 0 and <B>TIME</B> &gt; 0, both <B>MIN</B> and <B>TIME</B>
play a role in that <B>MIN</B> is satisfied with the receipt of a single
character.
<P></P>
<LI>Also note that in case A (<B>MIN</B> &gt; 0, <B>TIME</B> &gt; 0),
<B>TIME</B> represents an intercharacter timer, whereas in case C (<B>TIME</B>
= 0, <B>TIME</B> &gt; 0), <B>TIME</B> represents a read timer. </LI></UL>These
two points highlight the dual purpose of the <B>MIN/TIME</B> feature. Cases A
and B, where <B>MIN</B> &gt; 0, exist to handle burst mode activity (for
example, file transfer programs), where a program would like to process at least
<B>MIN</B> characters at a time. In case A, the intercharacter timer is
activated by a user as a safety measure; in case B, the timer is turned off.
<P>Cases C and D exist to handle single character, timed transfers. These cases
are readily adaptable to screen-based applications that need to know if a
character is present in the input queue before refreshing the screen. In case C,
the read is timed, whereas in case D, it is not.
<P>Another important note is that <B>MIN</B> is always just a minimum. It does
not denote a record length. For example, if a program does a read of 20 bytes,
<B>MIN</B> is 10, and 25 characters are present, then 20 characters will be
returned to the user.
<H3>Writing characters</H3>When one or more characters are written, they are
transmitted to the terminal as soon as previously written characters have
finished typing. Input characters are echoed as they are typed if echoing has
been enabled. If a process produces characters more rapidly than they can be
typed, it will be suspended when its output queue exceeds some limit. When the
queue is drained down to some threshold, the program is resumed.
<H3>Special characters</H3>Certain characters have special functions on input.
These functions and their default character values are summarized as follows:
<DL compact>
<P>
<DT><B>INTR</B>
<DD>(Rubout or ASCII &lt;Del&gt;) generates a <B>SIGINT</B> signal.
<B>SIGINT</B> is sent to all frequent processes associated with the
controlling terminal. Normally, each such process is forced to terminate, but
arrangements may be made either to ignore the signal or to receive a trap to
an agreed upon location. (See <A
href="http://docsrv.caldera.com/cgi-bin/man/man?signal+2"><B>signal</B>(2)</A>).
<P></P>
<DT><B>QUIT</B>
<DD>(<B>CTRL</B>-| or ASCII <B>FS</B>) generates a <B>SIGQUIT</B> signal. Its
treatment is identical to the interrupt signal except that, unless a receiving
process has made other arrangements, it will not only be terminated but a core
image file (called <I>core</I>) will be created in the current working
directory.
<P></P>
<DT><B>ERASE</B>
<DD>(&lt;Ctrl&gt;<B>H</B>) erases the preceding character. It does not erase
beyond the start of a line, as delimited by a <B>NL</B>, <B>EOF</B>,
<B>EOL</B>, or <B>EOL2</B> character.
<P></P>
<DT><B>WERASE</B>
<DD>(&lt;Ctrl&gt;<B>W</B> or ASCII <B>ETX</B>) erases the preceding ``word''.
It does not erase beyond the start of a line, as delimited by a <B>NL</B>,
<B>EOF</B>, <B>EOL</B>, or <B>EOL2</B> character.
<P></P>
<DT><B>KILL</B>
<DD>(&lt;Ctrl&gt;<B>U</B>) deletes the entire line, as delimited by a
<B>NL</B>, <B>EOF</B>, <B>EOL</B>, or <B>EOL2</B> character.
<P></P>
<DT><B>REPRINT</B>
<DD>(&lt;Ctrl&gt;<B>R</B> or ASCII <B>DC2</B>) reprints all characters,
preceded by a newline, that have not been read.
<P></P>
<DT><B>EOF</B>
<DD>(&lt;Ctrl&gt;<B>D</B> or ASCII <B>EOT</B>) may be used to generate an
end-of-file from a terminal. When received, all the characters waiting to be
read are immediately passed to the program, without waiting for a newline, and
the <B>EOF</B> is discarded. Thus, if no characters are waiting (that is, the
<B>EOF</B> occurred at the beginning of a line) zero characters are passed
back, which is the standard end-of-file indication. The <B>EOF</B> character
is not echoed unless it is escaped or <B>ECHOCTL</B> is set. Because
<B>EOT</B> is the default <B>EOF</B> character, this prevents terminals that
respond to <B>EOT</B> from hanging up.
<P></P>
<DT><B>NL</B>
<DD>(ASCII <B>LF</B>) is the normal line delimiter. It cannot be changed or
escaped.
<P></P>
<DT><B>EOL</B>
<DD>is an additional line delimiter, like <B>NL</B>. It is not normally used.
<P></P>
<DT><B>EOL2</B>
<DD>is another line delimiter.
<P></P>
<DT><B>SWTCH</B>
<DD>is used only when <B>shl</B> layers is invoked.
<P></P>
<DT><B>SUSP</B>
<DD>(&lt;Ctrl&gt;<B>Z</B> or ASCII <B>SUB</B>) generates a <B>SIGTSTP</B>
signal. <B>SIGTSTP</B> stops all processes in the foreground process group for
that terminal.
<P></P>
<DT><B>DSUSP</B>
<DD>(&lt;Ctrl&gt;<B>Y</B> or ASCII <B>EM</B> It generates a <B>SIGTSTP</B>
signal as <B>SUSP</B> does, but the signal is sent when a process in the
foreground process group attempts to read the <B>DSUSP</B> character, rather
than when it is typed.
<P></P>
<DT><B>STOP</B>
<DD>(&lt;Ctrl&gt;<B>S</B> or ASCII <B>DC3</B>) can be used to suspend output
temporarily. It is useful with CRT terminals to prevent output from
disappearing before it can be read. While output is suspended, <B>STOP</B>
characters are ignored and not read.
<P></P>
<DT><B>START</B>
<DD>(&lt;Ctrl&gt;<B>Q</B> or ASCII <B>DC1</B>) is used to resume output.
Output has been suspended by a <B>STOP</B> character. While output is not
suspended, <B>START</B> characters are ignored and not read.
<P></P>
<DT><B>DISCARD</B>
<DD>(&lt;Ctrl&gt;<B>O</B> or ASCII <B>SI</B>) causes subsequent output to be
discarded. Output is discarded until another <B>DISCARD</B> character is
typed, more input arrives, or the condition is cleared by a program.
<P></P>
<DT><B>LNEXT</B>
<DD>(&lt;Ctrl&gt;<B>V</B> or ASCII <B>SYN</B>) causes the special meaning of
the next character to be ignored. This works for all the special characters
mentioned above. It allows characters to be input that would otherwise be
interpreted by the system (for example, <B>KILL</B>, <B>QUIT</B>). </DD></DL>
<P>The character values for <B>INTR</B>, <B>QUIT</B>, <B>ERASE</B>,
<B>WERASE</B>, <B>KILL</B>, <B>REPRINT</B>, <B>EOF</B>, <B>EOL</B>, <B>EOL2</B>,
<B>SWTCH</B>, <B>SUSP</B>, <B>DSUSP</B>, <B>STOP</B>, <B>START</B>,
<B>DISCARD</B>, and <B>LNEXT</B> may be changed to suit individual tastes. If
the value of a special control character is <B>_POSIX_VDISABLE</B>, the function
of that special control character is disabled. The <B>ERASE</B>, <B>KILL</B>,
and <B>EOF</B> characters may be escaped by a preceding ``\'' character, in
which case no special function is done. Any of the special characters may be
preceded by the <B>LNEXT</B> character, in which case no special function is
done.
<H3>Modem disconnect</H3>When a modem disconnect is detected, a <B>SIGHUP</B>
signal is sent to the terminal's controlling process. Unless other arrangements
have been made, these signals cause the process to terminate. If <B>SIGHUP</B>
is ignored or caught, any subsequent read returns with an end-of-file indication
until the terminal is closed.
<P>Processes in background process groups that attempt to access the controlling
terminal after modem disconnect while the terminal is still allocated to the
session will receive appropriate <B>SIGTTOU</B> and <B>SIGTTIN</B> signals.
Unless other arrangements have been made, this signal causes the processes to
stop.
<P>The controlling terminal will remain in this state until it is reinitialized
with a successful open by the controlling process, or deallocated by the
controlling process.
<H3>Terminal parameters</H3>The parameters that control the behavior of devices
and modules providing the <B>termios</B> interface are specified by the
<B>termios</B> structure defined by <I>termios.h</I>. Several <A
href="http://docsrv.caldera.com/cgi-bin/man/man?ioctl+2"><B>ioctl</B>(2)</A>
system calls that fetch or change these parameters use this structure that
contains the following members: <PRE>tcflag_t c_iflag; /* input modes */
tcflag_t c_oflag; /* output modes */
tcflag_t c_cflag; /* control modes */
tcflag_t c_lflag; /* local modes */
cc_t c_cc[NCCS]; /* control chars */
</PRE>The special control characters are defined by the array <CODE>c_cc</CODE>.
The symbolic name <B>NCCS</B> is the size of the control character array and is
also defined by <I>termios.h</I>. The relative positions, subscript names, and
typical default values for each function are as follows: <NOSCRIPT><BR>[If this
table is unreadable, a preformatted table follows]<BR></NOSCRIPT>
<P>
<TABLE border=1>
<TBODY>
<TR vAlign=top>
<TH align=left>Position </TH>
<TH align=left>Name </TH>
<TH align=left>Default value </TH></TR>
<TR vAlign=top>
<TD>0 </TD>
<TD><B>VINTR</B> </TD>
<TD><B>DEL</B> </TD></TR>
<TR vAlign=top>
<TD>1 </TD>
<TD><B>VQUIT</B> </TD>
<TD><B>FS</B> </TD></TR>
<TR vAlign=top>
<TD>2 </TD>
<TD><B>VERASE</B> </TD>
<TD><B>BS</B> </TD></TR>
<TR vAlign=top>
<TD>3 </TD>
<TD><B>VKILL</B> </TD>
<TD><B>NAK</B> </TD></TR>
<TR vAlign=top>
<TD>4 </TD>
<TD><B>VEOF</B> </TD>
<TD><B>EOT</B> </TD></TR>
<TR vAlign=top>
<TD>5 </TD>
<TD><B>VEOL</B> </TD>
<TD><B>NUL</B> </TD></TR>
<TR vAlign=top>
<TD>6 </TD>
<TD><B>VEOL2</B> </TD>
<TD><B>NUL</B> </TD></TR>
<TR vAlign=top>
<TD>7 </TD>
<TD><B>VSWTCH</B> </TD>
<TD><B>NUL</B> </TD></TR>
<TR vAlign=top>
<TD>8 </TD>
<TD><B>VSTRT</B> </TD>
<TD><B>DC1</B> </TD></TR>
<TR vAlign=top>
<TD>9 </TD>
<TD><B>VSTOP</B> </TD>
<TD><B>DC3</B> </TD></TR>
<TR vAlign=top>
<TD>10 </TD>
<TD><B>VSUSP</B> </TD>
<TD><B>SUB</B> </TD></TR>
<TR vAlign=top>
<TD>11 </TD>
<TD><B>VDSUSP</B> </TD>
<TD><B>EM</B> </TD></TR>
<TR vAlign=top>
<TD>12 </TD>
<TD><B>VREPRINT</B> </TD>
<TD><B>DC2</B> </TD></TR>
<TR vAlign=top>
<TD>13 </TD>
<TD><B>VDISCRD</B> </TD>
<TD><B>SI</B> </TD></TR>
<TR vAlign=top>
<TD>14 </TD>
<TD><B>VWERASE</B> </TD>
<TD><B>ETB</B> </TD></TR>
<TR vAlign=top>
<TD>15 </TD>
<TD><B>VLNEXT</B> </TD>
<TD><B>SYN</B> </TD></TR>
<TR vAlign=top>
<TD>16-19 </TD>
<TD>reserved </TD>
<TD>&nbsp; </TD></TR></TBODY></TABLE><NOSCRIPT><PRE> -----------------------------------------
| Position | Name | Default value|
|----------|------------|----------------|
| 0 | <B>VINTR</B> | <B>DEL</B> |
|----------|------------|----------------|
| 1 | <B>VQUIT</B> | <B>FS</B> |
|----------|------------|----------------|
| 2 | <B>VERASE</B> | <B>BS</B> |
|----------|------------|----------------|
| 3 | <B>VKILL</B> | <B>NAK</B> |
|----------|------------|----------------|
| 4 | <B>VEOF</B> | <B>EOT</B> |
|----------|------------|----------------|
| 5 | <B>VEOL</B> | <B>NUL</B> |
|----------|------------|----------------|
| 6 | <B>VEOL2</B> | <B>NUL</B> |
|----------|------------|----------------|
| 7 | <B>VSWTCH</B> | <B>NUL</B> |
|----------|------------|----------------|
| 8 | <B>VSTRT</B> | <B>DC1</B> |
|----------|------------|----------------|
| 9 | <B>VSTOP</B> | <B>DC3</B> |
|----------|------------|----------------|
| 10 | <B>VSUSP</B> | <B>SUB</B> |
|----------|------------|----------------|
| 11 | <B>VDSUSP</B> | <B>EM</B> |
|----------|------------|----------------|
| 12 | <B>VREPRINT</B> | <B>DC2</B> |
|----------|------------|----------------|
| 13 | <B>VDISCRD</B> | <B>SI</B> |
|----------|------------|----------------|
| 14 | <B>VWERASE</B> | <B>ETB</B> |
|----------|------------|----------------|
| 15 | <B>VLNEXT</B> | <B>SYN</B> |
|----------|------------|----------------|
| 16-19 | reserved | |
|----------|------------|----------------|
</PRE></NOSCRIPT>
<P>For the non-canonical mode the positions of <B>VEOF</B> and <B>VEOL</B> are
shared by <B>VMIN</B> and <B>VTIME</B>: <NOSCRIPT><BR>[If this table is
unreadable, a preformatted table follows]<BR></NOSCRIPT>
<P>
<TABLE border=1>
<TBODY>
<TR vAlign=top>
<TH align=left>Position </TH>
<TH align=left>Name </TH>
<TH align=left>Default value </TH></TR>
<TR vAlign=top>
<TD>4 </TD>
<TD><B>VMIN</B> </TD>
<TD>used to set the value of <B>MIN</B> </TD></TR>
<TR vAlign=top>
<TD>5 </TD>
<TD><B>VTIME</B> </TD>
<TD>used to set the value of <B>TIME</B> </TD></TR></TBODY></TABLE><NOSCRIPT><PRE> ------------------------------------------------------
| Position | Name | Default value |
|----------|---------|--------------------------------|
| 4 | <B>VMIN</B> | used to set the value of <B>MIN</B> |
|----------|---------|--------------------------------|
| 5 | <B>VTIME</B> | used to set the value of <B>TIME</B>|
|----------|---------|--------------------------------|
</PRE></NOSCRIPT>
<H3>Input modes</H3>The <B><I>c_iflag</I></B> field describes the basic terminal
input control:
<DL compact>
<P>
<DT><B>IGNBRK</B>
<DD>Ignore break condition.
<P></P>
<DT><B>BRKINT</B>
<DD>Signal interrupt on break.
<P></P>
<DT><B>IGNPAR</B>
<DD>Ignore characters with parity errors.
<P></P>
<DT><B>PARMRK</B>
<DD>Mark parity errors.
<P></P>
<DT><B>INPCK</B>
<DD>Enable input parity check.
<P></P>
<DT><B>ISTRIP</B>
<DD>Strip character.
<P></P>
<DT><B>INLCR</B>
<DD>Map <B>NL</B> to <B>CR</B> on input.
<P></P>
<DT><B>IGNCR</B>
<DD>Ignore <B>CR</B>.
<P></P>
<DT><B>ICRNL</B>
<DD>Map <B>CR</B> to <B>NL</B> on input.
<P></P>
<DT><B>IUCLC</B>
<DD>Map upper-case to lower-case on input.
<P></P>
<DT><B>IXON</B>
<DD>Enable start/stop output control.
<P></P>
<DT><B>IXANY</B>
<DD>Enable any character to restart output.
<P></P>
<DT><B>IXOFF</B>
<DD>Enable start/stop input control.
<P></P>
<DT><B>IMAXBEL</B>
<DD>Echo <B>BEL</B> on input line too long. </DD></DL>If <B>IGNBRK</B> is set, a
break condition (a character framing error with data all zeros) detected on
input is ignored, that is, not put on the input queue and therefore not read by
any process. If <B>IGNBRK</B> is not set and <B>BRKINT</B> is set, the break
condition shall flush the input and output queues and if the terminal is the
controlling terminal of a foreground process group, the break condition
generates a single <B>SIGINT</B> signal to that foreground process group. If
neither <B>IGNBRK</B> nor <B>BRKINT</B> is set, a break condition is read as a
single ASCII <B>NULL</B> character (``\0''), or if <B>PARMRK</B> is set, as
``\377'', ``\0'', ``\0''.
<P>If <B>IGNPAR</B> is set, a byte with framing or parity errors (other than
break) is ignored.
<P>If <B>PARMRK</B> is set, and <B>IGNPAR</B> is not set, a byte with a framing
or parity error (other than break) is given to the application as the
three-character sequence: ``\377'', ``\0'', <B><I>X</I></B>, where
<B><I>X</I></B> is the data of the byte received in error. To avoid ambiguity in
this case, if <B>ISTRIP</B> is not set, a valid character of ``\377'' is given
to the application as ``\377'', ``\377''. If neither <B>IGNPAR</B> nor
<B>PARMRK</B> is set, a framing or parity error (other than break) is given to
the application as a single ASCII <B>NULL</B> character (``\0'').
<P>If <B>INPCK</B> is set, input parity checking is enabled. If <B>INPCK</B> is
not set, input parity checking is disabled. This allows output parity generation
without input parity errors. Note that whether input parity checking is enabled
or disabled is independent of whether parity detection is enabled or disabled.
If parity detection is enabled but input parity checking is disabled, the
hardware to which the terminal is connected will recognize the parity bit, but
the terminal special file will not check whether this is set correctly or not.
<P>If <B>ISTRIP</B> is set, valid input characters are first stripped to seven
bits, otherwise all eight bits are processed.
<P>If <B>INLCR</B> is set, a received <B>NL</B> character is translated into a
<B>CR</B> character. If <B>IGNCR</B> is set, a received <B>CR</B> character is
ignored (not read). Otherwise, if <B>ICRNL</B> is set, a received <B>CR</B>
character is translated into a <B>NL</B> character.
<P>If <B>IUCLC</B> is set, a received upper case, alphabetic character is
translated into the corresponding lower case character.
<P>If <B>IXON</B> is set, start/stop output control is enabled. A received
<B>STOP</B> character suspends output and a received <B>START</B> character
restarts output. The <B>STOP</B> and <B>START</B> characters will not be read,
but will merely perform flow control functions. If <B>IXANY</B> is set, any
input character restarts output that has been suspended.
<P>If <B>IXOFF</B> is set, the system transmits a <B>STOP</B> character when the
input queue is nearly full, and a <B>START</B> character when enough input has
been read so that the input queue is nearly empty again.
<P>If <B>IMAXBEL</B> is set, the ASCII <B>BEL</B> character is echoed if the
input stream overflows. Further input is not stored, but any input already
present in the input stream is not disturbed. If <B>IMAXBEL</B> is not set, no
<B>BEL</B> character is echoed, and all input present in the input queue is
discarded if the input stream overflows.
<P>The initial input control value is <B>BRKINT</B>, <B>ICRNL</B>, <B>IXON</B>,
<B>ISTRIP</B>.
<H3>Output modes</H3>The <B><I>c_oflag</I></B> field specifies the system
treatment of output:
<DL compact>
<P>
<DT><B>OPOST</B>
<DD>Post-process output.
<P></P>
<DT><B>OLCUC</B>
<DD>Map lower case to upper on output.
<P></P>
<DT><B>ONLCR</B>
<DD>Map <B>NL</B> to <B>CR-NL</B> on output.
<P></P>
<DT><B>OCRNL</B>
<DD>Map <B>CR</B> to <B>NL</B> on output.
<P></P>
<DT><B>ONOCR</B>
<DD>No <B>CR</B> output at column 0.
<P></P>
<DT><B>ONLRET</B>
<DD><B>NL</B> performs <B>CR</B> function.
<P></P>
<DT><B>OFILL</B>
<DD>Use fill characters for delay.
<P></P>
<DT><B>OFDEL</B>
<DD>Fill is <B>DEL</B>, else <B>NULL</B>.
<P></P>
<DT><B>NLDLY</B>
<DD>Select newline delays:
<UL>
<P>
<LI><B>NL0</B>
<P></P>
<LI><B>NL1</B> </LI></UL>
<P></P>
<DT><B>CRDLY</B>
<DD>Select carriage-return delays:
<UL>
<P>
<LI><B>CR0</B>
<P></P>
<LI><B>CR1</B>
<P></P>
<LI><B>CR2</B>
<P></P>
<LI><B>CR3</B> </LI></UL>
<P></P>
<DT><B>TABDLY</B>
<DD>Select horizontal tab delays:
<UL>
<P>
<LI><B>TAB0</B> </LI></UL>or tab expansion:
<UL>
<P>
<LI><B>TAB1</B>
<P></P>
<LI><B>TAB2</B>
<P></P>
<LI><B>TAB3</B> Expand tabs to spaces. </LI></UL>
<P></P>
<DT><B>XTABS</B>
<DD>Expand tabs to spaces.
<P></P>
<DT><B>BSDLY</B>
<DD>Select backspace delays:
<UL>
<P>
<LI><B>BS0</B>
<P></P>
<LI><B>BS1</B> </LI></UL>
<P></P>
<DT><B>VTDLY</B>
<DD>Select vertical tab delays:
<UL>
<P>
<LI><B>VT0</B>
<P></P>
<LI><B>VT1</B> </LI></UL>
<P></P>
<DT><B>FFDLY</B>
<DD>Select form feed delays:
<UL>
<P>
<LI><B>FF0</B>
<P></P>
<LI><B>FF1</B> </LI></UL></DD></DL>If <B>OPOST</B> is set, output characters are
post-processed as indicated by the remaining flags; otherwise, characters are
transmitted without change.
<P>If <B>OLCUC</B> is set, a lower case alphabetic character is transmitted as
the corresponding upper case character. This function is often used in
conjunction with <B>IUCLC</B>.
<P>If <B>ONLCR</B> is set, the <B>NL</B> character is transmitted as the
<B>CR-NL</B> character pair. If <B>OCRNL</B> is set, the <B>CR</B> character is
transmitted as the <B>NL</B> character. If <B>ONOCR</B> is set, no <B>CR</B>
character is transmitted when at column 0 (first position). If <B>ONRET</B> is
set, the <B>NL</B> character is assumed to do the carriage-return function; the
column pointer is set to 0 and the delays specified for <B>CR</B> are used.
Otherwise, the <B>NL</B> character is assumed to do just the line-feed function;
the column pointer remains unchanged. The column pointer is also set to 0 if the
<B>CR</B> character is actually transmitted.
<P>The delay bits specify how long transmission stops to allow for mechanical or
other movement when certain characters are sent to the terminal. In all cases, a
value of 0 indicates no delay. If <B>OFILL</B> is set, fill characters are
transmitted for delay instead of a timed delay. This is useful for high baud
rate terminals that need only a minimal delay. If <B>OFDEL</B> is set, the fill
character is <B>DEL</B>; otherwise it is <B>NULL</B>.
<P>If a form-feed or vertical-tab delay is specified, it lasts for about 2
seconds.
<P>Newline delay lasts about 0.10 seconds. If <B>ONLRET</B> is set, the
carriage-return delays are used instead of the newline delays. If <B>OFILL</B>
is set, two fill characters are transmitted.
<P>Carriage-return delay type 1 is dependent on the current column position,
type 2 is about 0.10 seconds, and type 3 is about 0.15 seconds. If <B>OFILL</B>
is set, delay type 1 transmits two fill characters, and type 2 transmits four
fill characters.
<P>Horizontal-tab delay type 1 is dependent on the current column position. Type
2 is about 0.10 seconds. Type 3 specifies that tabs are to be expanded into
spaces. If <B>OFILL</B> is set, two fill characters are transmitted for any
delay.
<P>Backspace delay lasts about 0.05 seconds. If <B>OFILL</B> is set, one fill
character is transmitted.
<P>The actual delays depend on line speed and system load.
<P>The initial output control value is <B>OPOST</B>, <B>ONLCR</B>, <B>TAB3</B>.
<H3>Control modes</H3>The <B><I>c_cflag</I></B> field describes the hardware
control of the terminal:
<DL compact>
<P>
<DT><B>CBAUD</B>
<DD>Baud rate:
<DL compact>
<P>
<DT><B>B0</B>
<DD>Hang up
<P></P>
<DT><B>B50</B>
<DD>50 baud
<P></P>
<DT><B>B75</B>
<DD>75 baud
<P></P>
<DT><B>B110</B>
<DD>110 baud
<P></P>
<DT><B>B134</B>
<DD>134 baud
<P></P>
<DT><B>B150</B>
<DD>150 baud
<P></P>
<DT><B>B200</B>
<DD>200 baud
<P></P>
<DT><B>B300</B>
<DD>300 baud
<P></P>
<DT><B>B600</B>
<DD>600 baud
<P></P>
<DT><B>B1200</B>
<DD>1200 baud
<P></P>
<DT><B>B1800</B>
<DD>1800 baud
<P></P>
<DT><B>B2400</B>
<DD>2400 baud
<P></P>
<DT><B>B4800</B>
<DD>4800 baud
<P></P>
<DT><B>B9600</B>
<DD>9600 baud
<P></P>
<DT><B>B19200</B>
<DD>19200 baud
<P></P>
<DT><B>EXTA</B>
<DD>External A
<P></P>
<DT><B>B38400</B>
<DD>38400 baud
<P></P>
<DT><B>EXTB</B>
<DD>External B </DD></DL>
<P></P>
<DT><B>E</B>
<DD>Character size:
<DL compact>
<P>
<DT><B>CS5</B>
<DD>5 bits
<P></P>
<DT><B>CS6</B>
<DD>6 bits
<P></P>
<DT><B>CS7</B>
<DD>7 bits
<P></P>
<DT><B>CS8</B>
<DD>8 bits </DD></DL>
<P></P>
<DT><B>PB</B>
<DD>Send two stop bits, else one
<P></P>
<DT><B>CREAD</B>
<DD>Enable receiver
<P></P>
<DT><B>PARENB</B>
<DD>Parity enable
<P></P>
<DT><B>PARODD</B>
<DD>Odd parity, else even
<P></P>
<DT><B>HUPCL</B>
<DD>Hang up on last close
<P></P>
<DT><B>CLOCAL</B>
<DD>Local line, else dial-up
<P></P>
<DT><B>CIBAUD</B>
<DD>Input baud rate, if different from output rate
<P></P>
<DT><B>PAREXT</B>
<DD>Extended parity for mark and space parity </DD></DL>The <B>CBAUD</B> bits
specify the baud rate. The zero baud rate, B0, is used to hang up the
connection. If B0 is specified, the data-terminal-ready signal is not asserted.
Normally, this disconnects the line. If the <B>CIBAUD</B> bits are not zero,
they specify the input baud rate, with the <B>NBAUD</B> bits specifying the
output baud rate; otherwise, the output and input baud rates are both specified
by the <B>CBAUD</B> bits. The values for the <B>CIBAUD</B> bits are the same as
the values for the <B>CBAUD</B> bits, shifted left <B>IBSHIFT</B> bits. For any
particular hardware, impossible speed changes are ignored.
<P>The <B>CSIZE</B> bits specify the character size in bits for both
transmission and reception. This size does not include the parity bit, if any.
If <B>CSTOPB</B> is set, two stop bits are used; otherwise, one stop bit is
used. For example, at 110 baud, two stops bits are required.
<P>If <B>PARENB</B> is set, parity generation and detection is enabled, and a
parity bit is added to each character. If parity is enabled, the <B>PARODD</B>
flag specifies odd parity if set; otherwise, even parity is used.
<P>If <B>CREAD</B> is set, the receiver is enabled. Otherwise, no characters are
received.
<P>If <B>HUPCL</B> is set, the line is disconnected when the last process with
the line open closes it or terminates. That is, the data-terminal-ready signal
is not asserted.
<P>If <B>CLOCAL</B> is set, the line is assumed to be a local, direct connection
with no modem control; otherwise, modem control is assumed.
<P>The initial hardware control value after open is <B>B300, CS8, CREAD,
HUPCL</B>.
<H3>Local modes</H3>The <B><I>c_lflag</I></B> field of the argument structure is
used by the line discipline to control terminal functions. The basic line
discipline provides the following:
<DL compact>
<P>
<DT><B>ISIG</B>
<DD>Enable signals.
<P></P>
<DT><B>ICANON</B>
<DD>Canonical input (erase and kill processing).
<P></P>
<DT><B>XCASE</B>
<DD>Canonical upper/lower presentation.
<P></P>
<DT><B>ECHO</B>
<DD>Enable echo.
<P></P>
<DT><B>ECHOE</B>
<DD>Echo erase character as <B>BS-SP-BS</B>.
<P></P>
<DT><B>ECHOK</B>
<DD>Echo <B>NL</B> after kill character.
<P></P>
<DT><B>ECHONL</B>
<DD>Echo <B>NL</B>.
<P></P>
<DT><B>NOFLSH</B>
<DD>Disable flush after interrupt or quit.
<P></P>
<DT><B>TOSTOP</B>
<DD>Send <B>SIGTTOU</B> for background output.
<P></P>
<DT><B>ECHOCTL</B>
<DD>Echo control characters as ^<B><I>char</I></B>, delete as ^?.
<P></P>
<DT><B>ECHOPRT</B>
<DD>Echo erase character as character erased.
<P></P>
<DT><B>ECHOKE</B>
<DD><B>BS-SP-BS</B> erase entire line on line kill.
<P></P>
<DT><B>FLUSHO</B>
<DD>Output is being flushed.
<P></P>
<DT><B>PENDIN</B>
<DD>Retype pending input at next read or input character.
<P></P>
<DT><B>IEXTEN</B>
<DD>Enable extended (implementation-defined) functions. </DD></DL>
<P>If <B>ISIG</B> is set, each input character is checked against the special
control characters <B>INTR</B>, <B>QUIT</B>, <B>SWTCH</B>, <B>SUSP</B>,
<B>STATUS</B>, and <B>DSUSP</B>. If an input character matches one of these
control characters, the function associated with that character is performed. If
<B>ISIG</B> is not set, no checking is done. Thus, these special input functions
are possible only if <B>ISIG</B> is set.
<P>If <B>ICANON</B> is set, canonical processing is enabled. This enables the
erase and kill edit functions, and the assembly of input characters into lines
delimited by <B>NL</B>, <B>EOF</B>, <B>EOL</B>, and <B>EOL2</B>. If
<B>ICANON</B> is not set, read requests are satisfied directly from the input
queue. A read is not satisfied until at least <B>MIN</B> characters have been
received or the timeout value <B>TIME</B> has expired between characters. This
allows fast bursts of input to be read efficiently while still allowing single
character input. The time value represents tenths of seconds.
<P>If <B>XCASE</B> is set, and if <B>ICANON</B> is set, an upper case letter is
accepted on input by preceding it with a ``e'' character, and is output preceded
by a ``e'' character. In this mode, the following escape sequences are generated
on output and accepted on input: <NOSCRIPT><BR>[If this table is unreadable, a
preformatted table follows]<BR></NOSCRIPT>
<P>
<TABLE border=1>
<TBODY>
<TR vAlign=top>
<TH align=left>For: </TH>
<TH align=left>Use: </TH></TR>
<TR vAlign=top>
<TD>` </TD>
<TD>\<5C> </TD></TR>
<TR vAlign=top>
<TD>| </TD>
<TD>\! </TD></TR>
<TR vAlign=top>
<TD>~ </TD>
<TD>\^ </TD></TR>
<TR vAlign=top>
<TD>{ </TD>
<TD>\( </TD></TR>
<TR vAlign=top>
<TD>} </TD>
<TD>\) </TD></TR>
<TR vAlign=top>
<TD>\ </TD>
<TD>\\ </TD></TR></TBODY></TABLE><NOSCRIPT><PRE> For: Use:
` \<5C>
| \!
~ \^
{ \(
} \)
\ \\
</PRE></NOSCRIPT>
<P>For example, ``A'' is input as ``\a'', ``\n'' as ``\\n'', and ``\N'' as
``\\\n''.
<P>If <B>ECHO</B> is set, characters are echoed as received.
<P>When <B>ICANON</B> is set, the following echo functions are possible:
<UL>
<P>
<LI>If <B>ECHO</B> and <B>ECHOE</B> are set, and <B>ECHOPRT</B> is not set,
the <B>ERASE</B> and <B>WERASE</B> characters are echoed as one or more ASCII
<B>BS SP BS</B>, which clears the last character(s) from a <B>CRT</B> screen.
<P></P>
<LI>If <B>ECHO</B> and <B>ECHOPRT</B> are set, the first <B>ERASE</B> and
<B>WERASE</B> character in a sequence echoes as a backslash (``\''), followed
by the characters being erased. Subsequent <B>ERASE</B> and <B>WERASE</B>
characters echo the characters being erased, in reverse order. The next
non-erase character causes a slash (``/'') to be typed before it is echoed.
<B>ECHOPRT</B> should be used for hard copy terminals.
<P></P>
<LI>If <B>ECHOKE</B> is set, the kill character is echoed by erasing each
character on the line from the screen (using the mechanism selected by
<B>ECHOE</B> and <B>ECHOPRT</B>).
<P></P>
<LI>If <B>ECHOK</B> is set, and <B>ECHOKE</B> is not set, the <B>NL</B>
character is echoed after the kill character to emphasize that the line is
deleted. Note that an escape character (``\'') or an <B>LNEXT</B> character
preceding the erase or kill character removes any special function.
<P></P>
<LI>If <B>ECHONL</B> is set, the <B>NL</B> character is echoed even if
<B>ECHO</B> is not set. This is useful for terminals set to local echo (so
called half-duplex). </LI></UL>If <B>ECHOCTL</B> is set, all control characters
(characters with codes between 0 and 37 octal) other than ASCII <B>TAB</B>,
ASCII <B>NL</B>, the <B>START</B> character, and the <B>STOP</B> character,
ASCII <B>CR</B>, and ASCII <B>BS</B> are echoed as ^<B><I>X</I></B>, where
<B><I>X</I></B> is the character given by adding 100 octal to the code of the
control character (so that the character with octal code 1 is echoed as ``^A''),
and the ASCII &lt;Del&gt; character, with octal code 177, is echoed as ``^?''.
<P>If <B>NOFLSH</B> is set, the normal flush of the input and output queues
associated with the <B>INTR</B>, <B>QUIT</B>, and <B>SUSP</B> characters is not
done. This bit should be set when restarting system calls that read from or
write to a terminal (see <A
href="http://docsrv.caldera.com/cgi-bin/man/man?sigaction+2"><B>sigaction</B>(2)</A>).
<P>If <B>TOSTOP</B> is set, the signal <B>SIGTTOU</B> is sent to a process that
tries to write to its controlling terminal if it is not in the foreground
process group for that terminal. This signal normally stops the process.
Otherwise, the output generated by that process is output to the current output
stream. Processes that are blocking or ignoring <B>SIGTTOU</B> signals are
excepted and allowed to produce output, if any.
<P>If <B>FLUSHO</B> is set, data written to the terminal is discarded. This bit
is set when the <B>FLUSH</B> character is typed. A program can cancel the effect
of typing the <B>FLUSH</B> character by clearing <B>FLUSHO</B>.
<P>If <B>PENDIN</B> is set, any input that has not yet been read is reprinted
when the next character arrives as input.
<P>If <B>IEXTEN</B> is set, the following implementation-defined functions are
enabled: special characters (<B>WERASE</B>, <B>REPRINT</B>, <B>DISCARD</B>, and
<B>LNEXT</B>) and local flags (<B>TOSTOP</B>, <B>ECHOCTL</B>, <B>ECHOPRT</B>,
<B>ECHOKE</B>, <B>FLUSHO</B>, and <B>PENDIN</B>).
<P>The initial line-discipline control value is <B>ISIG</B>, <B>ICANON</B>,
<B>ECHO</B>, <B>ECHOK</B>.
<H3>Terminal size</H3>The number of lines and columns on the terminal's display
is specified in the <B>winsize</B> structure defined by <I>sys/termios.h</I> and
includes the following members: <PRE>unsigned short ws_row; /* rows, in characters */
unsigned short ws_col; /* columns, in characters */
unsigned short ws_xpixel;/* horizontal size, in pixels */
unsigned short ws_ypixel;/* vertical size, in pixels */
</PRE>
<H3>termio structure</H3>The System V <B>termio</B> structure is used by some
<B>ioctl</B>s; it is defined by <I>sys/termio.h</I> and includes the following
members: <PRE>unsigned short c_iflag; /* input modes */
unsigned short c_oflag; /* output modes */
unsigned short c_cflag; /* control modes */
unsigned short c_lflag; /* local modes */
char c_line; /* line discipline */
unsigned char c_cc[NCC]; /* control chars */
</PRE>The special control characters are defined by the array <CODE>c_cc</CODE>.
The symbolic name <B>NCC</B> is the size of the control character array and is
also defined by <I>termio.h</I>. The relative positions, subscript names, and
typical default values for each function are as follows: <NOSCRIPT><BR>[If this
table is unreadable, a preformatted table follows]<BR></NOSCRIPT>
<P>
<TABLE border=1>
<TBODY>
<TR vAlign=top>
<TH align=left>Position </TH>
<TH align=left>Name </TH>
<TH align=left>Default value </TH></TR>
<TR vAlign=top>
<TD>0 </TD>
<TD><B>VINTR</B> </TD>
<TD><B>DEL</B> </TD></TR>
<TR vAlign=top>
<TD>1 </TD>
<TD><B>VQUIT</B> </TD>
<TD><B>FS</B> </TD></TR>
<TR vAlign=top>
<TD>2 </TD>
<TD><B>VERASE</B> </TD>
<TD><B>BS</B> </TD></TR>
<TR vAlign=top>
<TD>3 </TD>
<TD><B>VKILL</B> </TD>
<TD><B>NAK</B> </TD></TR>
<TR vAlign=top>
<TD>4 </TD>
<TD><B>VEOF</B> </TD>
<TD><B>EOT</B> </TD></TR>
<TR vAlign=top>
<TD>5 </TD>
<TD><B>VEOL</B> </TD>
<TD><B>NUL</B> </TD></TR>
<TR vAlign=top>
<TD>6 </TD>
<TD><B>VEOL2</B> </TD>
<TD><B>NUL</B> </TD></TR>
<TR vAlign=top>
<TD>7 </TD>
<TD>reserved </TD>
<TD>&nbsp; </TD></TR></TBODY></TABLE><NOSCRIPT><PRE> -----------------------------------------
| Position | Name | Default value|
|----------|------------|----------------|
| 0 | <B>VINTR</B> | <B>DEL</B> |
|----------|------------|----------------|
| 1 | <B>VQUIT</B> | <B>FS</B> |
|----------|------------|----------------|
| 2 | <B>VERASE</B> | <B>BS</B> |
|----------|------------|----------------|
| 3 | <B>VKILL</B> | <B>NAK</B> |
|----------|------------|----------------|
| 4 | <B>VEOF</B> | <B>EOT</B> |
|----------|------------|----------------|
| 5 | <B>VEOL</B> | <B>NUL</B> |
|----------|------------|----------------|
| 6 | <B>VEOL2</B> | <B>NUL</B> |
|----------|------------|----------------|
| 7 | reserved | |
|----------|------------|----------------|
</PRE></NOSCRIPT>For the non-canonical mode the positions of <B>VEOF</B> and
<B>NEOL</B> are shared by <B>VMIN</B> and <B>VTIME</B>: <NOSCRIPT><BR>[If this
table is unreadable, a preformatted table follows]<BR></NOSCRIPT>
<P>
<TABLE border=1>
<TBODY>
<TR vAlign=top>
<TH align=left>Position </TH>
<TH align=left>Name </TH>
<TH align=left>Default value </TH></TR>
<TR vAlign=top>
<TD>4 </TD>
<TD><B>VMIN</B> </TD>
<TD>used to set the value of <B>MIN</B> </TD></TR>
<TR vAlign=top>
<TD>5 </TD>
<TD><B>VTIME</B> </TD>
<TD>used to set the value of <B>TIME</B> </TD></TR></TBODY></TABLE><NOSCRIPT><PRE> ------------------------------------------------------
| Position | Name | Default value |
|----------|---------|--------------------------------|
| 4 | <B>VMIN</B> | used to set the value of <B>MIN</B> |
|----------|---------|--------------------------------|
| 5 | <B>VTIME</B> | used to set the value of <B>TIME</B>|
|----------|---------|--------------------------------|
</PRE></NOSCRIPT>The calls that use the <B>termio</B> structure only affect the
flags and control characters that can be stored in the <B>termio</B> structure;
all other flags and control characters are unaffected.
<H3>Modem lines</H3>On special files representing serial ports, the modem
control lines supported by the hardware can be read, and the modem status lines
supported by the hardware can be changed. The following modem control and status
lines may be supported by a device; they are defined by <I>sys/termios.h</I>:
<DL compact>
<P>
<DT><B>TIOCM_LE</B>
<DD>line enable
<P></P>
<DT><B>TIOCMGET</B>/<B>TIOCMSET</B>
<DD>get/set line status, see <A
href="http://docsrv.caldera.com/cgi-bin/man/man?termio+7#termio7.ioctl_comms">``ioctl
commands''</A>
<P></P>
<DT><B>TIOCMBIC</B>/<B>TIOCMBIS</B>
<DD>clear/set lines, see <A
href="http://docsrv.caldera.com/cgi-bin/man/man?termio+7#termio7.ioctl_comms">``ioctl
commands''</A>
<P></P>
<DT><B>TIOCM_DTR</B>
<DD>data terminal ready
<P></P>
<DT><B>TIOCM_RTS</B>
<DD>request to send
<P></P>
<DT><B>TIOCM_ST</B>
<DD>secondary transmit
<P></P>
<DT><B>TIOCM_SR</B>
<DD>secondary receive
<P></P>
<DT><B>TIOCM_CTS</B>
<DD>clear to send
<P></P>
<DT><B>TIOCM_CAR</B>
<DD>carrier detect
<P></P>
<DT><B>TIOCM_RNG</B>
<DD>ring
<P></P>
<DT><B>TIOCM_DSR</B>
<DD>data set ready </DD></DL><B>TIOCM_CD</B> is a synonym for <B>TIOCM_CAR</B>,
and <B>TIOCM_RI</B> is a synonym for <B>TIOCM_RNG</B>. These are used by the
<B>TIOCMSET</B>, <B>TIOCMBIS</B>, <B>TIOCMGET</B> and <B>TIOCMBIC</B>
<B>ioctl</B>s. Not all of these are necessarily supported by any particular
device; check the manual page for the device in question. <A
name=termio7.ioctl_comms></A>
<H3>ioctl commands</H3>The <B>ioctl</B>s supported by devices and STREAMS
modules providing the <B>termios</B> interface are listed below. Some calls may
not be supported by all devices or modules. The functionality provided by these
calls is also available through the preferred function call interface specified
on <A
href="http://docsrv.caldera.com/cgi-bin/man/man?termios+3C"><B>termios</B>(3C)</A>.
<DL compact>
<P>
<DT><B>TCGETS</B>
<DD>The argument is a pointer to a <B>termios</B> structure. The current
terminal parameters are fetched and stored into that structure.
<P></P>
<DT><B>TCSETS</B>
<DD>The argument is a pointer to a <B>termios</B> structure. The current
terminal parameters are set from the values stored in that structure. The
change is immediate.
<P></P>
<DT><B>TCSETSW</B>
<DD>The argument is a pointer to a <B>termios</B> structure. The current
terminal parameters are set from the values stored in that structure. The
change occurs after all characters queued for output have been transmitted.
This form should be used when changing parameters that affect output.
<P></P>
<DT><B>TCSETSF</B>
<DD>The argument is a pointer to a <B>termios</B> structure. The current
terminal parameters are set from the values stored in that structure. The
change occurs after all characters queued for output have been transmitted;
all characters queued for input are discarded and then the change occurs.
<P></P>
<DT><B>TCGETA</B>
<DD>The argument is a pointer to a <B>termio</B> structure. The current
terminal parameters are fetched, and those parameters that can be stored in a
<B>termio</B> structure are stored into that structure.
<P></P>
<DT><B>TCSETA</B>
<DD>The argument is a pointer to a <B>termio</B> structure. Those terminal
parameters that can be stored in a <B>termio</B> structure are set from the
values stored in that structure. The change is immediate.
<P></P>
<DT><B>TCSETAW</B>
<DD>The argument is a pointer to a <B>termio</B> structure. Those terminal
parameters that can be stored in a <B>termio</B> structure are set from the
values stored in that structure. The change occurs after all characters queued
for output have been transmitted. This form should be used when changing
parameters that affect output.
<P></P>
<DT><B>TCSETAF</B>
<DD>The argument is a pointer to a <B>termio</B> structure. Those terminal
parameters that can be stored in a <B>termio</B> structure are set from the
values stored in that structure. The change occurs after all characters queued
for output have been transmitted; all characters queued for input are
discarded and then the change occurs.
<P></P>
<DT><B>TCSBRK</B>
<DD>The argument is an <B>int</B> value. Wait for the output to drain. If the
argument is 0, then send a break (zero valued bits for 0.25 seconds).
<P></P>
<DT><B>TCXONC</B>
<DD>Start/stop control. The argument is an <B>int</B> value. If the argument
is 0, suspend output; if 1, restart suspended output; if 2, suspend input; if
3, restart suspended input.
<P></P>
<DT><B>TCFLSH</B>
<DD>The argument is an <B>int</B> value. If the argument is 0, flush the input
queue; if 1, flush the output queue; if 2, flush both the input and output
queues. On some controllers, if the argument is 0, input flow control
characters will be flushed, causing the unflushed output queue to overflow a
busy output device.
<P></P>
<DT><B>TIOCGPGRP</B>
<DD>The argument is a pointer to a <B>pid_t</B>. Set the value of that
<B>pid_t</B> to the process group ID of the foreground process group
associated with the terminal. See <A
href="http://docsrv.caldera.com/cgi-bin/man/man?termios+3C"><B>termios</B>(3C)</A>
for a description of <B>TCGETPGRP</B>.
<P></P>
<DT><B>TIOCSPGRP</B>
<DD>The argument is a pointer to a <B>pid_t</B>. Associate the process group
whose process group ID is specified by the value of that <B>pid_t</B> with the
terminal. The new process group value must be in the range of valid process
group ID values. Otherwise, the error <B>EPERM</B> is returned. See <A
href="http://docsrv.caldera.com/cgi-bin/man/man?termios+3C"><B>termios</B>(3C)</A>
for a description of <B>TCSETPGRP</B>.
<P></P>
<DT><B>TIOCGSID</B>
<DD>The argument is a pointer to a <B>pid_t</B>. The session ID of the
terminal is fetched and stored in the <B>pid_t</B>.
<P></P>
<DT><B>TIOCGWINSZ</B>
<DD>The argument is a pointer to a <B>winsize</B> structure. The terminal
driver's notion of the terminal size is stored into that structure.
<P></P>
<DT><B>TIOCSWINSZ</B>
<DD>The argument is a pointer to a <B>winsize</B> structure. The terminal
driver's notion of the terminal size is set from the values specified in that
structure. If the new sizes are different from the old sizes, a
<B>SIGWINCH</B> signal is set to the process group of the terminal.
<P></P>
<DT><B>TIOCMBIS</B>/<B>TIOCMBIC</B>
<DD>Set/clear modem control lines (set to <B>TRUE</B>/<B>FALSE</B> state).
This is a pointer to an <B>int</B> which contains the modem line identifier
for the modem lines to be set to <B>TRUE</B>/<B>FALSE</B> (from the
<B>TIOCM_<IMG alt=* src="termio(7).files/lowast.gif"></B> definitions.
<P></P>
<DT><B>TIOCMGET</B>
<DD>Get the state of all the modem control lines in the <B>int</B> pointed to
be the argument (in the <B>TIOCM_<IMG alt=*
src="termio(7).files/lowast.gif"></B> definitions). If the bit is 0, then the
line is disasserted; if 1, the line is asserted.
<P></P>
<DT><B>TIOCMSET</B>
<DD>Set modem control line status. This is a pointer to an <B>int</B>. All
modem control lines are set to the value held in the <B>int</B>'s bit which
represents the line (in the <B>TIOCM_<IMG alt=*
src="termio(7).files/lowast.gif"></B> definitions. For example, to set the DTR
line to <B>FALSE</B>, set the <B>TIOCM_DTR</B> bit to 0; set the bit to 1 for
<B>TRUE</B>. </DD></DL>
<H2>Files</H2>
<DL compact>
<P>
<DT><I>/dev/*</I>
<DD></DD></DL>
<H2>References</H2><A
href="http://docsrv.caldera.com/cgi-bin/man/man?fork+2"><B>fork</B>(2)</A>, <A
href="http://docsrv.caldera.com/cgi-bin/man/man?ioctl+2"><B>ioctl</B>(2)</A>, <A
href="http://docsrv.caldera.com/cgi-bin/man/man?setsid+2"><B>setsid</B>(2)</A>,
<A
href="http://docsrv.caldera.com/cgi-bin/man/man?signal+2"><B>signal</B>(2)</A>,
<A
href="http://docsrv.caldera.com/cgi-bin/man/man?streamio+7"><B>streamio</B>(7)</A>,
<A
href="http://docsrv.caldera.com/cgi-bin/man/man?termios+3C"><B>termios</B>(3C)</A>
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<HR>
<I><SMALL>5 November 1999 <BR><A
href="http://docsrv.caldera.com/man/html.7/COPYRIGHT.html"><EFBFBD> 1999 The Santa Cruz
Operation, Inc. All rights reserved.</A> <BR>UnixWare 7 Release 7.1.1 - 5
November 1999 <BR></SMALL></I><!-- NAVEND --></BODY></HTML>
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