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diff --git a/static/freebsd/man4/termios.4 3.html b/static/freebsd/man4/termios.4 3.html deleted file mode 100644 index d3827e1e..00000000 --- a/static/freebsd/man4/termios.4 3.html +++ /dev/null @@ -1,1050 +0,0 @@ -<table class="head"> - <tr> - <td class="head-ltitle">TERMIOS(4)</td> - <td class="head-vol">Device Drivers Manual</td> - <td class="head-rtitle">TERMIOS(4)</td> - </tr> -</table> -<div class="manual-text"> -<section class="Sh"> -<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1> -<p class="Pp"><code class="Nm">termios</code> — <span class="Nd">general - terminal line discipline</span></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1> -<p class="Pp"><code class="In">#include - <<a class="In">termios.h</a>></code></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> -<p class="Pp">This describes a general terminal line discipline that is - supported on tty asynchronous communication ports.</p> -<section class="Ss"> -<h2 class="Ss" id="Opening_a_Terminal_Device_File"><a class="permalink" href="#Opening_a_Terminal_Device_File">Opening - a Terminal Device File</a></h2> -<p class="Pp">When a terminal file is opened, it normally causes the process to - wait until a connection is established. For most hardware, the presence of a - connection is indicated by the assertion of the hardware - <code class="Dv">CARRIER</code> line. If the termios structure associated - with the terminal file has the <code class="Dv">CLOCAL</code> flag set in - the cflag, or if the <code class="Dv">O_NONBLOCK</code> flag is set in the - <a class="Xr">open(2)</a> call, then the open will succeed even without a - connection being present. In practice, applications seldom open these files; - they are opened by special programs, such as <a class="Xr">getty(8)</a>, and - become an application's standard input, output, and error files.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Job_Control_in_a_Nutshell"><a class="permalink" href="#Job_Control_in_a_Nutshell">Job - Control in a Nutshell</a></h2> -<p class="Pp">Every process is associated with a particular process group and - session. The grouping is hierarchical: every member of a particular process - group is a member of the same session. This structuring is used in managing - groups of related processes for purposes of - <a class="permalink" href="#job"><i class="Em" id="job">job control</i></a>; - that is, the ability from the keyboard (or from program control) to - simultaneously stop or restart a complex command (a command composed of one - or more related processes). The grouping into process groups allows - delivering of signals that stop or start the group as a whole, along with - arbitrating which process group has access to the single controlling - terminal. The grouping at a higher layer into sessions is to restrict the - job control related signals and system calls to within processes resulting - from a particular instance of a “login”. Typically, a session - is created when a user logs in, and the login terminal is setup to be the - controlling terminal; all processes spawned from that login shell are in the - same session, and inherit the controlling terminal.</p> -<p class="Pp">A job control shell operating interactively (that is, reading - commands from a terminal) normally groups related processes together by - placing them into the same process group. A set of processes in the same - process group is collectively referred to as a “job”. When the - foreground process group of the terminal is the same as the process group of - a particular job, that job is said to be in the “foreground”. - When the process group of the terminal is different from the process group - of a job (but is still the controlling terminal), that job is said to be in - the “background”. Normally the shell reads a command and - starts the job that implements that command. If the command is to be started - in the foreground (typical), it sets the process group of the terminal to - the process group of the started job, waits for the job to complete, and - then sets the process group of the terminal back to its own process group - (it puts itself into the foreground). If the job is to be started in the - background (as denoted by the shell operator "&"), it never - changes the process group of the terminal and does not wait for the job to - complete (that is, it immediately attempts to read the next command). If the - job is started in the foreground, the user may type a key (usually - ‘<code class="Li">^Z</code>’) which generates the terminal - stop signal (<code class="Dv">SIGTSTP</code>) and has the effect of stopping - the entire job. The shell will notice that the job stopped, and will resume - running after placing itself in the foreground. The shell also has commands - for placing stopped jobs in the background, and for placing stopped or - background jobs into the foreground.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Orphaned_Process_Groups"><a class="permalink" href="#Orphaned_Process_Groups">Orphaned - Process Groups</a></h2> -<p class="Pp">An orphaned process group is a process group that has no process - whose parent is in a different process group, yet is in the same session. - Conceptually it means a process group that does not have a parent that could - do anything if it were to be stopped. For example, the initial login shell - is typically in an orphaned process group. Orphaned process groups are - immune to keyboard generated stop signals and job control signals resulting - from reads or writes to the controlling terminal.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="The_Controlling_Terminal"><a class="permalink" href="#The_Controlling_Terminal">The - Controlling Terminal</a></h2> -<p class="Pp">A terminal may belong to a process as its controlling terminal. - Each process of a session that has a controlling terminal has the same - controlling terminal. A terminal may be the controlling terminal for at most - one session. The controlling terminal for a session is allocated by the - session leader by issuing the <code class="Dv">TIOCSCTTY</code> ioctl. A - controlling terminal is never acquired by merely opening a terminal device - file. When a controlling terminal becomes associated with a session, its - foreground process group is set to the process group of the session - leader.</p> -<p class="Pp">The controlling terminal is inherited by a child process during a - <a class="Xr">fork(2)</a> function call. A process relinquishes its - controlling terminal when it creates a new session with the - <a class="Xr">setsid(2)</a> function; other processes remaining in the old - session that had this terminal as their controlling terminal continue to - have it. A process does not relinquish its controlling terminal simply by - closing all of its file descriptors associated with the controlling terminal - if other processes continue to have it open.</p> -<p class="Pp">When a controlling process terminates, the controlling terminal is - disassociated from the current session, allowing it to be acquired by a new - session leader. Subsequent access to the terminal by other processes in the - earlier session will be denied, with attempts to access the terminal treated - as if modem disconnect had been sensed.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Terminal_Access_Control"><a class="permalink" href="#Terminal_Access_Control">Terminal - Access Control</a></h2> -<p class="Pp">If a process is in the foreground process group of its controlling - terminal, read operations are allowed. Any attempts by a process in a - background process group to read from its controlling terminal causes a - <code class="Dv">SIGTTIN</code> signal to be sent to the process's group - unless one of the following special cases apply: if the reading process is - ignoring or blocking the <code class="Dv">SIGTTIN</code> signal, or if the - process group of the reading process is orphaned, the - <a class="Xr">read(2)</a> returns -1 with <var class="Va">errno</var> set to - <code class="Er">EIO</code> and no signal is sent. The default action of the - <code class="Dv">SIGTTIN</code> signal is to stop the process to which it is - sent.</p> -<p class="Pp">If a process is in the foreground process group of its controlling - terminal, write operations are allowed. Attempts by a process in a - background process group to write to its controlling terminal will cause the - process group to be sent a <code class="Dv">SIGTTOU</code> signal unless one - of the following special cases apply: if <code class="Dv">TOSTOP</code> is - not set, or if <code class="Dv">TOSTOP</code> is set and the process is - ignoring or blocking the <code class="Dv">SIGTTOU</code> signal, the process - is allowed to write to the terminal and the <code class="Dv">SIGTTOU</code> - signal is not sent. If <code class="Dv">TOSTOP</code> is set, and the - process group of the writing process is orphaned, and the writing process is - not ignoring or blocking <code class="Dv">SIGTTOU</code>, the - <a class="Xr">write(2)</a> returns -1 with errno set to - <code class="Er">EIO</code> and no signal is sent.</p> -<p class="Pp">Certain calls that set terminal parameters are treated in the same - fashion as write, except that <code class="Dv">TOSTOP</code> is ignored; - that is, the effect is identical to that of terminal writes when - <code class="Dv">TOSTOP</code> is set.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Input_Processing_and_Reading_Data"><a class="permalink" href="#Input_Processing_and_Reading_Data">Input - Processing and Reading Data</a></h2> -<p class="Pp">A terminal device associated with a terminal device file may - operate in full-duplex mode, so that data may arrive even while output is - occurring. Each terminal device file has associated with it an input queue, - into which incoming data is stored by the system before being read by a - process. The system imposes a limit, {<code class="Dv">MAX_INPUT</code>}, on - the number of bytes that may be stored in the input queue. The behavior of - the system when this limit is exceeded depends on the setting of the - <code class="Dv">IMAXBEL</code> flag in the termios - <var class="Fa">c_iflag</var>. If this flag is set, the terminal is sent an - ASCII <code class="Dv">BEL</code> character each time a character is - received while the input queue is full. Otherwise, the input queue is - flushed upon receiving the character.</p> -<p class="Pp">Two general kinds of input processing are available, determined by - whether the terminal device file is in canonical mode or noncanonical mode. - Additionally, input characters are processed according to the - <var class="Fa">c_iflag</var> and <var class="Fa">c_lflag</var> fields. Such - processing can include echoing, which in general means transmitting input - characters immediately back to the terminal when they are received from the - terminal. This is useful for terminals that can operate in full-duplex - mode.</p> -<p class="Pp">The manner in which data is provided to a process reading from a - terminal device file is dependent on whether the terminal device file is in - canonical or noncanonical mode.</p> -<p class="Pp">Another dependency is whether the - <code class="Dv">O_NONBLOCK</code> flag is set by <a class="Xr">open(2)</a> - or <a class="Xr">fcntl(2)</a>. If the <code class="Dv">O_NONBLOCK</code> - flag is clear, then the read request is blocked until data is available or a - signal has been received. If the <code class="Dv">O_NONBLOCK</code> flag is - set, then the read request is completed, without blocking, in one of three - ways:</p> -<ol class="Bl-enum Bd-indent"> - <li>If there is enough data available to satisfy the entire request, and the - read completes successfully the number of bytes read is returned.</li> - <li>If there is not enough data available to satisfy the entire request, and - the read completes successfully, having read as much data as possible, the - number of bytes read is returned.</li> - <li>If there is no data available, the read returns -1, with errno set to - <code class="Er">EAGAIN</code>.</li> -</ol> -<p class="Pp">When data is available depends on whether the input processing - mode is canonical or noncanonical.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Canonical_Mode_Input_Processing"><a class="permalink" href="#Canonical_Mode_Input_Processing">Canonical - Mode Input Processing</a></h2> -<p class="Pp">In canonical mode input processing, terminal input is processed in - units of lines. A line is delimited by a newline - ‘<code class="Li">\n</code>’ character, an end-of-file - (<code class="Dv">EOF</code>) character, or an end-of-line - (<code class="Dv">EOL</code>) character. See the - <a class="Sx" href="#Special_Characters">Special Characters</a> section for - more information on <code class="Dv">EOF</code> and - <code class="Dv">EOL</code>. This means that a read request will not return - until an entire line has been typed, or a signal has been received. Also, no - matter how many bytes are requested in the read call, at most one line is - returned. It is not, however, necessary to read a whole line at once; any - number of bytes, even one, may be requested in a read without losing - information.</p> -<p class="Pp">{<code class="Dv">MAX_CANON</code>} is a limit on the number of - bytes in a line. The behavior of the system when this limit is exceeded is - the same as when the input queue limit {<code class="Dv">MAX_INPUT</code>}, - is exceeded.</p> -<p class="Pp">Erase and kill processing occur when either of two special - characters, the <code class="Dv">ERASE</code> and - <code class="Dv">KILL</code> characters (see the - <a class="Sx" href="#Special_Characters">Special Characters</a> section), is - received. This processing affects data in the input queue that has not yet - been delimited by a newline <code class="Dv">NL</code>, - <code class="Dv">EOF</code>, or <code class="Dv">EOL</code> character. This - un-delimited data makes up the current line. The - <code class="Dv">ERASE</code> character deletes the last character in the - current line, if there is any. The <code class="Dv">KILL</code> character - deletes all data in the current line, if there is any. The - <code class="Dv">ERASE</code> and <code class="Dv">KILL</code> characters - have no effect if there is no data in the current line. The - <code class="Dv">ERASE</code> and <code class="Dv">KILL</code> characters - themselves are not placed in the input queue.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Noncanonical_Mode_Input_Processing"><a class="permalink" href="#Noncanonical_Mode_Input_Processing">Noncanonical - Mode Input Processing</a></h2> -<p class="Pp">In noncanonical mode input processing, input bytes are not - assembled into lines, and erase and kill processing does not occur. The - values of the <code class="Dv">VMIN</code> and <code class="Dv">VTIME</code> - members of the <var class="Fa">c_cc</var> array are used to determine how to - process the bytes received.</p> -<p class="Pp"><code class="Dv">MIN</code> represents the minimum number of bytes - that should be received when the <a class="Xr">read(2)</a> function - successfully returns. <code class="Dv">TIME</code> is a timer of 0.1 second - granularity that is used to time out bursty and short term data - transmissions. If <code class="Dv">MIN</code> is greater than - <code class="Dv">{</code> <code class="Dv">MAX_INPUT</code>}, the response - to the request is undefined. The four possible values for - <code class="Dv">MIN</code> and <code class="Dv">TIME</code> and their - interactions are described below.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Case_A:_MIN___0,_TIME___0"><a class="permalink" href="#Case_A:_MIN___0,_TIME___0">Case - A: MIN > 0, TIME > 0</a></h2> -<p class="Pp">In this case <code class="Dv">TIME</code> serves as an inter-byte - timer and is activated after the first byte is received. Since it is an - inter-byte timer, it is reset after a byte is received. The interaction - between <code class="Dv">MIN</code> and <code class="Dv">TIME</code> is as - follows: as soon as one byte is received, the inter-byte timer is started. - If <code class="Dv">MIN</code> bytes are received before the inter-byte - timer expires (remember that the timer is reset upon receipt of each byte), - the read is satisfied. If the timer expires before - <code class="Dv">MIN</code> bytes are received, the characters received to - that point are returned to the user. Note that if - <code class="Dv">TIME</code> expires at least one byte is returned because - the timer would not have been enabled unless a byte was received. In this - case (<code class="Dv">MIN</code> > 0, <code class="Dv">TIME</code> > - 0) the read blocks until the <code class="Dv">MIN</code> and - <code class="Dv">TIME</code> mechanisms are activated by the receipt of the - first byte, or a signal is received. If data is in the buffer at the time of - the - <a class="permalink" href="#read"><code class="Fn" id="read">read</code></a>(), - the result is as if data had been received immediately after the - <code class="Fn">read</code>().</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Case_B:_MIN___0,_TIME_=_0"><a class="permalink" href="#Case_B:_MIN___0,_TIME_=_0">Case - B: MIN > 0, TIME = 0</a></h2> -<p class="Pp">In this case, since the value of <code class="Dv">TIME</code> is - zero, the timer plays no role and only <code class="Dv">MIN</code> is - significant. A pending read is not satisfied until - <code class="Dv">MIN</code> bytes are received (i.e., the pending read - blocks until <code class="Dv">MIN</code> bytes are received), or a signal is - received. A program that uses this case to read record-based terminal - <code class="Dv">I/O</code> may block indefinitely in the read - operation.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Case_C:_MIN_=_0,_TIME___0"><a class="permalink" href="#Case_C:_MIN_=_0,_TIME___0">Case - C: MIN = 0, TIME > 0</a></h2> -<p class="Pp">In this case, since <code class="Dv">MIN</code> = 0, - <code class="Dv">TIME</code> no longer represents an inter-byte timer. It - now serves as a read timer that is activated as soon as the read function is - processed. A read is satisfied as soon as a single byte is received or the - read timer expires. Note that in this case if the timer expires, no bytes - are returned. If the timer does not expire, the only way the read can be - satisfied is if a byte is received. In this case the read will not block - indefinitely waiting for a byte; if no byte is received within - <code class="Dv">TIME</code>*0.1 seconds after the read is initiated, the - read returns a value of zero, having read no data. If data is in the buffer - at the time of the read, the timer is started as if data had been received - immediately after the read.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Case_D:_MIN_=_0,_TIME_=_0"><a class="permalink" href="#Case_D:_MIN_=_0,_TIME_=_0">Case - D: MIN = 0, TIME = 0</a></h2> -<p class="Pp">The minimum of either the number of bytes requested or the number - of bytes currently available is returned without waiting for more bytes to - be input. If no characters are available, read returns a value of zero, - having read no data.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Writing_Data_and_Output_Processing"><a class="permalink" href="#Writing_Data_and_Output_Processing">Writing - Data and Output Processing</a></h2> -<p class="Pp">When a process writes one or more bytes to a terminal device file, - they are processed according to the <var class="Fa">c_oflag</var> field (see - the <a class="Sx" href="#Output_Modes">Output Modes</a> section). The - implementation may provide a buffering mechanism; as such, when a call to - <code class="Fn">write</code>() completes, all of the bytes written have - been scheduled for transmission to the device, but the transmission will not - necessarily have been completed.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Special_Characters"><a class="permalink" href="#Special_Characters">Special - Characters</a></h2> -<p class="Pp">Certain characters have special functions on input or output or - both. These functions are summarized as follows:</p> -<dl class="Bl-tag"> - <dt id="INTR"><a class="permalink" href="#INTR"><code class="Dv">INTR</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ISIG</code> flag (see the - <a class="Sx" href="#Local_Modes">Local Modes</a> section) is enabled. - Generates a <code class="Dv">SIGINT</code> signal which is sent to all - processes in the foreground process group for which the terminal is the - controlling terminal. If <code class="Dv">ISIG</code> is set, the - <code class="Dv">INTR</code> character is discarded when processed.</dd> - <dt id="QUIT"><a class="permalink" href="#QUIT"><code class="Dv">QUIT</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ISIG</code> flag is enabled. Generates a - <code class="Dv">SIGQUIT</code> signal which is sent to all processes in - the foreground process group for which the terminal is the controlling - terminal. If <code class="Dv">ISIG</code> is set, the - <code class="Dv">QUIT</code> character is discarded when processed.</dd> - <dt id="ERASE"><a class="permalink" href="#ERASE"><code class="Dv">ERASE</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. Erases the last character in - the current line; see - <a class="Sx" href="#Canonical_Mode_Input_Processing">Canonical Mode Input - Processing</a>. It does not erase beyond the start of a line, as delimited - by an <code class="Dv">NL</code>, <code class="Dv">EOF</code>, or - <code class="Dv">EOL</code> character. If <code class="Dv">ICANON</code> - is set, the <code class="Dv">ERASE</code> character is discarded when - processed.</dd> - <dt id="KILL"><a class="permalink" href="#KILL"><code class="Dv">KILL</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. Deletes the entire line, as - delimited by a <code class="Dv">NL</code>, <code class="Dv">EOF</code>, or - <code class="Dv">EOL</code> character. If <code class="Dv">ICANON</code> - is set, the <code class="Dv">KILL</code> character is discarded when - processed.</dd> - <dt id="EOF"><a class="permalink" href="#EOF"><code class="Dv">EOF</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. When received, all the bytes - waiting to be read are immediately passed to the process, without waiting - for a newline, and the <code class="Dv">EOF</code> is discarded. Thus, if - there are no bytes waiting (that is, the <code class="Dv">EOF</code> - occurred at the beginning of a line), a byte count of zero is returned - from the <code class="Fn">read</code>(), representing an end-of-file - indication. If <code class="Dv">ICANON</code> is set, the - <code class="Dv">EOF</code> character is discarded when processed.</dd> - <dt id="NL"><a class="permalink" href="#NL"><code class="Dv">NL</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. It is the line delimiter - ‘<code class="Li">\n</code>’.</dd> - <dt id="EOL"><a class="permalink" href="#EOL"><code class="Dv">EOL</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. Is an additional line - delimiter, like <code class="Dv">NL</code>.</dd> - <dt id="SUSP"><a class="permalink" href="#SUSP"><code class="Dv">SUSP</code></a></dt> - <dd>If the <code class="Dv">ISIG</code> flag is enabled, receipt of the - <code class="Dv">SUSP</code> character causes a - <code class="Dv">SIGTSTP</code> signal to be sent to all processes in the - foreground process group for which the terminal is the controlling - terminal, and the <code class="Dv">SUSP</code> character is discarded when - processed.</dd> - <dt id="STOP"><a class="permalink" href="#STOP"><code class="Dv">STOP</code></a></dt> - <dd>Special character on both input and output and is recognized if the - <code class="Dv">IXON</code> (output control) or - <code class="Dv">IXOFF</code> (input control) flag is set. Can be used to - temporarily suspend output. It is useful with fast terminals to prevent - output from disappearing before it can be read. If - <code class="Dv">IXON</code> is set, the <code class="Dv">STOP</code> - character is discarded when processed.</dd> - <dt id="START"><a class="permalink" href="#START"><code class="Dv">START</code></a></dt> - <dd>Special character on both input and output and is recognized if the - <code class="Dv">IXON</code> (output control) or - <code class="Dv">IXOFF</code> (input control) flag is set. Can be used to - resume output that has been suspended by a <code class="Dv">STOP</code> - character. If <code class="Dv">IXON</code> is set, the - <code class="Dv">START</code> character is discarded when processed.</dd> - <dt id="CR"><a class="permalink" href="#CR"><code class="Dv">CR</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set; it is the - ‘<code class="Li">\r</code>’, as denoted in the C Standard - {2}. When <code class="Dv">ICANON</code> and <code class="Dv">ICRNL</code> - are set and <code class="Dv">IGNCR</code> is not set, this character is - translated into a <code class="Dv">NL</code>, and has the same effect as a - <code class="Dv">NL</code> character.</dd> -</dl> -<p class="Pp">The following special characters are extensions defined by this - system and are not a part of <span class="St">IEEE Std 1003.1 - (“POSIX.1”)</span> termios.</p> -<dl class="Bl-tag"> - <dt id="EOL2"><a class="permalink" href="#EOL2"><code class="Dv">EOL2</code></a></dt> - <dd>Secondary <code class="Dv">EOL</code> character. Same function as - <code class="Dv">EOL</code>.</dd> - <dt id="WERASE"><a class="permalink" href="#WERASE"><code class="Dv">WERASE</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. Erases the last word in the - current line according to one of two algorithms. If the - <code class="Dv">ALTWERASE</code> flag is not set, first any preceding - whitespace is erased, and then the maximal sequence of non-whitespace - characters. If <code class="Dv">ALTWERASE</code> is set, first any - preceding whitespace is erased, and then the maximal sequence of - alphabetic/underscores or non alphabetic/underscores. As a special case in - this second algorithm, the first previous non-whitespace character is - skipped in determining whether the preceding word is a sequence of - alphabetic/underscores. This sounds confusing but turns out to be quite - practical.</dd> - <dt id="REPRINT"><a class="permalink" href="#REPRINT"><code class="Dv">REPRINT</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. Causes the current input edit - line to be retyped.</dd> - <dt id="DSUSP"><a class="permalink" href="#DSUSP"><code class="Dv">DSUSP</code></a></dt> - <dd>Has similar actions to the <code class="Dv">SUSP</code> character, except - that the <code class="Dv">SIGTSTP</code> signal is delivered when one of - the processes in the foreground process group issues a - <a class="permalink" href="#read~2"><code class="Fn" id="read~2">read</code></a>() - to the controlling terminal.</dd> - <dt id="LNEXT"><a class="permalink" href="#LNEXT"><code class="Dv">LNEXT</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">IEXTEN</code> flag is set. Receipt of this character - causes the next character to be taken literally.</dd> - <dt id="DISCARD"><a class="permalink" href="#DISCARD"><code class="Dv">DISCARD</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">IEXTEN</code> flag is set. Receipt of this character - toggles the flushing of terminal output.</dd> - <dt id="STATUS"><a class="permalink" href="#STATUS"><code class="Dv">STATUS</code></a></dt> - <dd>Special character on input and is recognized if the - <code class="Dv">ICANON</code> flag is set. Receipt of this character - causes a <code class="Dv">SIGINFO</code> signal to be sent to the - foreground process group of the terminal. Also, if the - <code class="Dv">NOKERNINFO</code> flag is not set, it causes the kernel - to write a status message to the terminal that displays the current load - average, the name of the command in the foreground, its process ID, the - symbolic wait channel, the number of user and system seconds used, the - percentage of cpu the process is getting, and the resident set size of the - process. - <p class="Pp">In case the kernel has <a class="Xr">stack(9)</a> support - configured and the <a class="Xr">sysctl(8)</a> variable - <var class="Va">kern.tty_info_kstacks</var> is set to a non-zero value, - the running thread's kernel stack is written to the terminal (e.g., for - debugging purposes).</p> - </dd> -</dl> -<p class="Pp">The <code class="Dv">NL</code> and <code class="Dv">CR</code> - characters cannot be changed. The values for all the remaining characters - can be set and are described later in the document under Special Control - Characters.</p> -<p class="Pp">Special character functions associated with changeable special - control characters can be disabled individually by setting their value to - <code class="Dv">{_POSIX_VDISABLE}</code>; see - <a class="Sx" href="#Special_Control_Characters">Special Control - Characters</a>.</p> -<p class="Pp">If two or more special characters have the same value, the - function performed when that character is received is undefined.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Modem_Disconnect"><a class="permalink" href="#Modem_Disconnect">Modem - Disconnect</a></h2> -<p class="Pp">If a modem disconnect is detected by the terminal interface for a - controlling terminal, and if <code class="Dv">CLOCAL</code> is not set in - the <var class="Fa">c_cflag</var> field for the terminal, the - <code class="Dv">SIGHUP</code> signal is sent to the controlling process - associated with the terminal. Unless other arrangements have been made, this - causes the controlling process to terminate. Any subsequent call to the - <a class="permalink" href="#read~3"><code class="Fn" id="read~3">read</code></a>() - function returns the value zero, indicating end of file. Thus, processes - that read a terminal file and test for end-of-file can terminate - appropriately after a disconnect. Any subsequent - <a class="permalink" href="#write"><code class="Fn" id="write">write</code></a>() - to the terminal device returns -1, with <var class="Va">errno</var> set to - <code class="Er">EIO</code>, until the device is closed.</p> -</section> -</section> -<section class="Sh"> -<h1 class="Sh" id="General_Terminal_Interface"><a class="permalink" href="#General_Terminal_Interface">General - Terminal Interface</a></h1> -<section class="Ss"> -<h2 class="Ss" id="Closing_a_Terminal_Device_File"><a class="permalink" href="#Closing_a_Terminal_Device_File">Closing - a Terminal Device File</a></h2> -<p class="Pp">The last process to close a terminal device file causes any output - to be sent to the device and any input to be discarded. Then, if - <code class="Dv">HUPCL</code> is set in the control modes, and the - communications port supports a disconnect function, the terminal device - performs a disconnect.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Parameters_That_Can_Be_Set"><a class="permalink" href="#Parameters_That_Can_Be_Set">Parameters - That Can Be Set</a></h2> -<p class="Pp">Routines that need to control certain terminal I/O characteristics - do so by using the termios structure as defined in the header - <code class="In"><<a class="In">termios.h</a>></code>. This structure - contains minimally four scalar elements of bit flags and one array of - special characters. The scalar flag elements are named: - <var class="Fa">c_iflag</var>, <var class="Fa">c_oflag</var>, - <var class="Fa">c_cflag</var>, and <var class="Fa">c_lflag</var>. The - character array is named <var class="Fa">c_cc</var>, and its maximum index - is <code class="Dv">NCCS</code>.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Input_Modes"><a class="permalink" href="#Input_Modes">Input - Modes</a></h2> -<p class="Pp">Values of the <var class="Fa">c_iflag</var> field describe the - basic terminal input control, and are composed of following masks:</p> -<p class="Pp"></p> -<div class="Bd-indent"> -<dl class="Bl-tag Bl-compact"> - <dt id="IGNBRK"><a class="permalink" href="#IGNBRK"><code class="Dv">IGNBRK</code></a></dt> - <dd>/* ignore BREAK condition */</dd> - <dt id="BRKINT"><a class="permalink" href="#BRKINT"><code class="Dv">BRKINT</code></a></dt> - <dd>/* map BREAK to SIGINTR */</dd> - <dt id="IGNPAR"><a class="permalink" href="#IGNPAR"><code class="Dv">IGNPAR</code></a></dt> - <dd>/* ignore (discard) parity errors */</dd> - <dt id="PARMRK"><a class="permalink" href="#PARMRK"><code class="Dv">PARMRK</code></a></dt> - <dd>/* mark parity and framing errors */</dd> - <dt id="INPCK"><a class="permalink" href="#INPCK"><code class="Dv">INPCK</code></a></dt> - <dd>/* enable checking of parity errors */</dd> - <dt id="ISTRIP"><a class="permalink" href="#ISTRIP"><code class="Dv">ISTRIP</code></a></dt> - <dd>/* strip 8th bit off chars */</dd> - <dt id="INLCR"><a class="permalink" href="#INLCR"><code class="Dv">INLCR</code></a></dt> - <dd>/* map NL into CR */</dd> - <dt id="IGNCR"><a class="permalink" href="#IGNCR"><code class="Dv">IGNCR</code></a></dt> - <dd>/* ignore CR */</dd> - <dt id="ICRNL"><a class="permalink" href="#ICRNL"><code class="Dv">ICRNL</code></a></dt> - <dd>/* map CR to NL (ala CRMOD) */</dd> - <dt id="IXON"><a class="permalink" href="#IXON"><code class="Dv">IXON</code></a></dt> - <dd>/* enable output flow control */</dd> - <dt id="IXOFF"><a class="permalink" href="#IXOFF"><code class="Dv">IXOFF</code></a></dt> - <dd>/* enable input flow control */</dd> - <dt id="IXANY"><a class="permalink" href="#IXANY"><code class="Dv">IXANY</code></a></dt> - <dd>/* any char will restart after stop */</dd> - <dt id="IMAXBEL"><a class="permalink" href="#IMAXBEL"><code class="Dv">IMAXBEL</code></a></dt> - <dd>/* ring bell on input queue full */</dd> - <dt id="IUTF8"><a class="permalink" href="#IUTF8"><code class="Dv">IUTF8</code></a></dt> - <dd>/* assume input is UTF-8 encoded */</dd> -</dl> -</div> -<p class="Pp">In the context of asynchronous serial data transmission, a break - condition is defined as a sequence of zero-valued bits that continues for - more than the time to send one byte. The entire sequence of zero-valued bits - is interpreted as a single break condition, even if it continues for a time - equivalent to more than one byte. In contexts other than asynchronous serial - data transmission the definition of a break condition is implementation - defined.</p> -<p class="Pp">If <code class="Dv">IGNBRK</code> is set, a break condition - detected on input is ignored, that is, not put on the input queue and - therefore not read by any process. If <code class="Dv">IGNBRK</code> is not - set and <code class="Dv">BRKINT</code> is set, the break condition flushes - the input and output queues and if the terminal is the controlling terminal - of a foreground process group, the break condition generates a single - <code class="Dv">SIGINT</code> signal to that foreground process group. If - neither <code class="Dv">IGNBRK</code> nor <code class="Dv">BRKINT</code> is - set, a break condition is read as a single - ‘<code class="Li">\0</code>’, or if - <code class="Dv">PARMRK</code> is set, as - ‘<code class="Li">\377</code>’, - ‘<code class="Li">\0</code>’, - ‘<code class="Li">\0</code>’.</p> -<p class="Pp">If <code class="Dv">IGNPAR</code> is set, a byte with a framing or - parity error (other than break) is ignored.</p> -<p class="Pp">If <code class="Dv">PARMRK</code> is set, and - <code class="Dv">IGNPAR</code> is not set, a byte with a framing or parity - error (other than break) is given to the application as the three-character - sequence ‘<code class="Li">\377</code>’, - ‘<code class="Li">\0</code>’, X, where - ‘<code class="Li">\377</code>’, - ‘<code class="Li">\0</code>’ is a two-character flag preceding - each sequence and X is the data of the character received in error. To avoid - ambiguity in this case, if <code class="Dv">ISTRIP</code> is not set, a - valid character of ‘<code class="Li">\377</code>’ is given to - the application as ‘<code class="Li">\377</code>’, - ‘<code class="Li">\377</code>’. If neither - <code class="Dv">PARMRK</code> nor <code class="Dv">IGNPAR</code> is set, a - framing or parity error (other than break) is given to the application as a - single character ‘<code class="Li">\0</code>’.</p> -<p class="Pp">If <code class="Dv">INPCK</code> is set, input parity checking is - enabled. If <code class="Dv">INPCK</code> is not set, input parity checking - is disabled, allowing 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 (see - <a class="Sx" href="#Control_Modes">Control Modes</a>). If parity detection - is enabled but input parity checking is disabled, the hardware to which the - terminal is connected recognizes the parity bit, but the terminal special - file does not check whether this bit is set correctly or not.</p> -<p class="Pp">If <code class="Dv">ISTRIP</code> is set, valid input bytes are - first stripped to seven bits, otherwise all eight bits are processed.</p> -<p class="Pp">If <code class="Dv">INLCR</code> is set, a received - <code class="Dv">NL</code> character is translated into a - <code class="Dv">CR</code> character. If <code class="Dv">IGNCR</code> is - set, a received <code class="Dv">CR</code> character is ignored (not read). - If <code class="Dv">IGNCR</code> is not set and - <code class="Dv">ICRNL</code> is set, a received <code class="Dv">CR</code> - character is translated into a <code class="Dv">NL</code> character.</p> -<p class="Pp">If <code class="Dv">IXON</code> is set, start/stop output control - is enabled. A received <code class="Dv">STOP</code> character suspends - output and a received <code class="Dv">START</code> character restarts - output. If <code class="Dv">IXANY</code> is also set, then any character may - restart output. When <code class="Dv">IXON</code> is set, - <code class="Dv">START</code> and <code class="Dv">STOP</code> characters - are not read, but merely perform flow control functions. When - <code class="Dv">IXON</code> is not set, the <code class="Dv">START</code> - and <code class="Dv">STOP</code> characters are read.</p> -<p class="Pp">If <code class="Dv">IXOFF</code> is set, start/stop input control - is enabled. The system shall transmit one or more - <code class="Dv">STOP</code> characters, which are intended to cause the - terminal device to stop transmitting data, as needed to prevent the input - queue from overflowing and causing the undefined behavior described in - <a class="Sx" href="#Input_Processing_and_Reading_Data">Input Processing and - Reading Data</a>, and shall transmit one or more - <code class="Dv">START</code> characters, which are intended to cause the - terminal device to resume transmitting data, as soon as the device can - continue transmitting data without risk of overflowing the input queue. The - precise conditions under which <code class="Dv">STOP</code> and - <code class="Dv">START</code> characters are transmitted are implementation - defined.</p> -<p class="Pp">If <code class="Dv">IMAXBEL</code> is set and the input queue is - full, subsequent input shall cause an ASCII <code class="Dv">BEL</code> - character to be transmitted to the output queue.</p> -<p class="Pp" id="open">The initial input control value after - <a class="permalink" href="#open"><code class="Fn">open</code></a>() is - implementation defined.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Output_Modes"><a class="permalink" href="#Output_Modes">Output - Modes</a></h2> -<p class="Pp">Values of the <var class="Fa">c_oflag</var> field describe the - basic terminal output control, and are composed of the following masks:</p> -<p class="Pp"></p> -<div class="Bd-indent"> -<dl class="Bl-tag Bl-compact"> - <dt id="OPOST"><a class="permalink" href="#OPOST"><code class="Dv">OPOST</code></a></dt> - <dd>/* enable following output processing */</dd> - <dt id="ONLCR"><a class="permalink" href="#ONLCR"><code class="Dv">ONLCR</code></a></dt> - <dd>/* map NL to CR-NL (ala <code class="Dv">CRMOD</code>) */</dd> - <dt id="OCRNL"><a class="permalink" href="#OCRNL"><code class="Dv">OCRNL</code></a></dt> - <dd>/* map CR to NL */</dd> - <dt id="TABDLY"><a class="permalink" href="#TABDLY"><code class="Dv">TABDLY</code></a></dt> - <dd>/* tab delay mask */</dd> - <dt id="TAB0"><a class="permalink" href="#TAB0"><code class="Dv">TAB0</code></a></dt> - <dd>/* no tab delay and expansion */</dd> - <dt id="TAB3"><a class="permalink" href="#TAB3"><code class="Dv">TAB3</code></a></dt> - <dd>/* expand tabs to spaces */</dd> - <dt id="ONOEOT"><a class="permalink" href="#ONOEOT"><code class="Dv">ONOEOT</code></a></dt> - <dd>/* discard <code class="Dv">EOT</code>'s - ‘<code class="Li">^D</code>’ on output) */</dd> - <dt id="ONOCR"><a class="permalink" href="#ONOCR"><code class="Dv">ONOCR</code></a></dt> - <dd>/* do not transmit CRs on column 0 */</dd> - <dt id="ONLRET"><a class="permalink" href="#ONLRET"><code class="Dv">ONLRET</code></a></dt> - <dd>/* on the terminal NL performs the CR function */</dd> -</dl> -</div> -<p class="Pp">If <code class="Dv">OPOST</code> is set, the remaining flag masks - are interpreted as follows; otherwise characters are transmitted without - change.</p> -<p class="Pp">If <code class="Dv">ONLCR</code> is set, newlines are translated - to carriage return, linefeeds.</p> -<p class="Pp">If <code class="Dv">OCRNL</code> is set, carriage returns are - translated to newlines.</p> -<p class="Pp">The <code class="Dv">TABDLY</code> bits specify the tab delay. The - <var class="Fa">c_oflag</var> is masked with <code class="Dv">TABDLY</code> - and compared with the values <code class="Dv">TAB0</code> or - <code class="Dv">TAB3</code>. If <code class="Dv">TAB3</code> is set, tabs - are expanded to the appropriate number of spaces (assuming 8 column tab - stops).</p> -<p class="Pp">If <code class="Dv">ONOEOT</code> is set, ASCII - <code class="Dv">EOT</code>'s are discarded on output.</p> -<p class="Pp">If <code class="Dv">ONOCR</code> is set, no CR character is - transmitted when at column 0 (first position).</p> -<p class="Pp">If <code class="Dv">ONLRET</code> is set, the NL character is - assumed to do the carriage-return function; the column pointer will be set - to 0.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Control_Modes"><a class="permalink" href="#Control_Modes">Control - Modes</a></h2> -<p class="Pp">Values of the <var class="Fa">c_cflag</var> field describe the - basic terminal hardware control, and are composed of the following masks. - Not all values specified are supported by all hardware.</p> -<p class="Pp"></p> -<div class="Bd-indent"> -<dl class="Bl-tag Bl-compact"> - <dt id="CSIZE"><a class="permalink" href="#CSIZE"><code class="Dv">CSIZE</code></a></dt> - <dd>/* character size mask */</dd> - <dt id="CS5"><a class="permalink" href="#CS5"><code class="Dv">CS5</code></a></dt> - <dd>/* 5 bits (pseudo) */</dd> - <dt id="CS6"><a class="permalink" href="#CS6"><code class="Dv">CS6</code></a></dt> - <dd>/* 6 bits */</dd> - <dt id="CS7"><a class="permalink" href="#CS7"><code class="Dv">CS7</code></a></dt> - <dd>/* 7 bits */</dd> - <dt id="CS8"><a class="permalink" href="#CS8"><code class="Dv">CS8</code></a></dt> - <dd>/* 8 bits */</dd> - <dt id="CSTOPB"><a class="permalink" href="#CSTOPB"><code class="Dv">CSTOPB</code></a></dt> - <dd>/* send 2 stop bits */</dd> - <dt id="CREAD"><a class="permalink" href="#CREAD"><code class="Dv">CREAD</code></a></dt> - <dd>/* enable receiver */</dd> - <dt id="PARENB"><a class="permalink" href="#PARENB"><code class="Dv">PARENB</code></a></dt> - <dd>/* parity enable */</dd> - <dt id="PARODD"><a class="permalink" href="#PARODD"><code class="Dv">PARODD</code></a></dt> - <dd>/* odd parity, else even */</dd> - <dt id="HUPCL"><a class="permalink" href="#HUPCL"><code class="Dv">HUPCL</code></a></dt> - <dd>/* hang up on last close */</dd> - <dt id="CLOCAL"><a class="permalink" href="#CLOCAL"><code class="Dv">CLOCAL</code></a></dt> - <dd>/* ignore modem status lines */</dd> - <dt id="CCTS_OFLOW"><a class="permalink" href="#CCTS_OFLOW"><code class="Dv">CCTS_OFLOW</code></a></dt> - <dd>/* <code class="Dv">CTS</code> flow control of output */</dd> - <dt id="CRTSCTS"><a class="permalink" href="#CRTSCTS"><code class="Dv">CRTSCTS</code></a></dt> - <dd>/* same as <code class="Dv">CCTS_OFLOW</code> */</dd> - <dt id="CRTS_IFLOW"><a class="permalink" href="#CRTS_IFLOW"><code class="Dv">CRTS_IFLOW</code></a></dt> - <dd>/* RTS flow control of input */</dd> - <dt id="MDMBUF"><a class="permalink" href="#MDMBUF"><code class="Dv">MDMBUF</code></a></dt> - <dd>/* flow control output via Carrier */</dd> - <dt id="CNO_RTSDTR"><a class="permalink" href="#CNO_RTSDTR"><code class="Dv">CNO_RTSDTR</code></a></dt> - <dd>/* Do not assert RTS or DTR automatically */</dd> -</dl> -</div> -<p class="Pp">The <code class="Dv">CSIZE</code> bits specify the byte size in - bits for both transmission and reception. The <var class="Fa">c_cflag</var> - is masked with <code class="Dv">CSIZE</code> and compared with the values - <code class="Dv">CS5</code>, <code class="Dv">CS6</code>, - <code class="Dv">CS7</code>, or <code class="Dv">CS8</code>. This size does - not include the parity bit, if any. If <code class="Dv">CSTOPB</code> is - set, two stop bits are used, otherwise one stop bit. For example, at 110 - baud, two stop bits are normally used.</p> -<p class="Pp">If <code class="Dv">CREAD</code> is set, the receiver is enabled. - Otherwise, no character is received. Not all hardware supports this bit. In - fact, this flag is pretty silly and if it were not part of the - <code class="Nm">termios</code> specification it would be omitted.</p> -<p class="Pp">If <code class="Dv">PARENB</code> is set, parity generation and - detection are enabled and a parity bit is added to each character. If parity - is enabled, <code class="Dv">PARODD</code> specifies odd parity if set, - otherwise even parity is used.</p> -<p class="Pp">If <code class="Dv">HUPCL</code> 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> -<p class="Pp">If <code class="Dv">CLOCAL</code> is set, a connection does not - depend on the state of the modem status lines. If - <code class="Dv">CLOCAL</code> is clear, the modem status lines are - monitored.</p> -<p class="Pp" id="open~2">Under normal circumstances, a call to the - <a class="permalink" href="#open~2"><code class="Fn">open</code></a>() - function waits for the modem connection to complete. However, if the - <code class="Dv">O_NONBLOCK</code> flag is set or if - <code class="Dv">CLOCAL</code> has been set, the - <code class="Fn">open</code>() function returns immediately without waiting - for the connection.</p> -<p class="Pp">The <code class="Dv">CCTS_OFLOW</code> - (<code class="Dv">CRTSCTS</code>) flag is currently unused.</p> -<p class="Pp">If <code class="Dv">MDMBUF</code> is set then output flow control - is controlled by the state of Carrier Detect.</p> -<p class="Pp">If <code class="Dv">CNO_RTSDTR</code> is set then the RTS and DTR - lines will not be asserted when the device is opened. As a result, this flag - is only useful on initial-state devices.</p> -<p class="Pp">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 it is directly connected - to.</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Local_Modes"><a class="permalink" href="#Local_Modes">Local - Modes</a></h2> -<p class="Pp">Values of the <var class="Fa">c_lflag</var> field describe the - control of various functions, and are composed of the following masks.</p> -<p class="Pp"></p> -<div class="Bd-indent"> -<dl class="Bl-tag Bl-compact"> - <dt id="ECHOKE"><a class="permalink" href="#ECHOKE"><code class="Dv">ECHOKE</code></a></dt> - <dd>/* visual erase for line kill */</dd> - <dt id="ECHOE"><a class="permalink" href="#ECHOE"><code class="Dv">ECHOE</code></a></dt> - <dd>/* visually erase chars */</dd> - <dt id="ECHO"><a class="permalink" href="#ECHO"><code class="Dv">ECHO</code></a></dt> - <dd>/* enable echoing */</dd> - <dt id="ECHONL"><a class="permalink" href="#ECHONL"><code class="Dv">ECHONL</code></a></dt> - <dd>/* echo <code class="Dv">NL</code> even if <code class="Dv">ECHO</code> is - off */</dd> - <dt id="ECHOPRT"><a class="permalink" href="#ECHOPRT"><code class="Dv">ECHOPRT</code></a></dt> - <dd>/* visual erase mode for hardcopy */</dd> - <dt id="ECHOCTL"><a class="permalink" href="#ECHOCTL"><code class="Dv">ECHOCTL</code></a></dt> - <dd>/* echo control chars as ^(Char) */</dd> - <dt id="ISIG"><a class="permalink" href="#ISIG"><code class="Dv">ISIG</code></a></dt> - <dd>/* enable signals <code class="Dv">INTR</code>, - <code class="Dv">QUIT</code>, <code class="Dv">[D]SUSP</code> */</dd> - <dt id="ICANON"><a class="permalink" href="#ICANON"><code class="Dv">ICANON</code></a></dt> - <dd>/* canonicalize input lines */</dd> - <dt id="ALTWERASE"><a class="permalink" href="#ALTWERASE"><code class="Dv">ALTWERASE</code></a></dt> - <dd>/* use alternate <code class="Dv">WERASE</code> algorithm */</dd> - <dt id="IEXTEN"><a class="permalink" href="#IEXTEN"><code class="Dv">IEXTEN</code></a></dt> - <dd>/* enable <code class="Dv">DISCARD</code> and - <code class="Dv">LNEXT</code> */</dd> - <dt id="EXTPROC"><a class="permalink" href="#EXTPROC"><code class="Dv">EXTPROC</code></a></dt> - <dd>/* external processing */</dd> - <dt id="TOSTOP"><a class="permalink" href="#TOSTOP"><code class="Dv">TOSTOP</code></a></dt> - <dd>/* stop background jobs from output */</dd> - <dt id="FLUSHO"><a class="permalink" href="#FLUSHO"><code class="Dv">FLUSHO</code></a></dt> - <dd>/* output being flushed (state) */</dd> - <dt id="NOKERNINFO"><a class="permalink" href="#NOKERNINFO"><code class="Dv">NOKERNINFO</code></a></dt> - <dd>/* no kernel output from <code class="Dv">VSTATUS</code> */</dd> - <dt id="PENDIN"><a class="permalink" href="#PENDIN"><code class="Dv">PENDIN</code></a></dt> - <dd>/* XXX retype pending input (state) */</dd> - <dt id="NOFLSH"><a class="permalink" href="#NOFLSH"><code class="Dv">NOFLSH</code></a></dt> - <dd>/* don't flush after interrupt */</dd> -</dl> -</div> -<p class="Pp">If <code class="Dv">ECHO</code> is set, input characters are - echoed back to the terminal. If <code class="Dv">ECHO</code> is not set, - input characters are not echoed.</p> -<p class="Pp">If <code class="Dv">ECHOE</code> and - <code class="Dv">ICANON</code> are set, the <code class="Dv">ERASE</code> - character causes the terminal to erase the last character in the current - line from the display, if possible. If there is no character to erase, an - implementation may echo an indication that this was the case or do - nothing.</p> -<p class="Pp">If <code class="Dv">ECHOK</code> and - <code class="Dv">ICANON</code> are set, the <code class="Dv">KILL</code> - character causes the current line to be discarded and the system echoes the - ‘<code class="Li">\n</code>’ character after the - <code class="Dv">KILL</code> character.</p> -<p class="Pp">If <code class="Dv">ECHOKE</code> and - <code class="Dv">ICANON</code> are set, the <code class="Dv">KILL</code> - character causes the current line to be discarded and the system causes the - terminal to erase the line from the display.</p> -<p class="Pp">If <code class="Dv">ECHOPRT</code> and - <code class="Dv">ICANON</code> are set, the system assumes that the display - is a printing device and prints a backslash and the erased characters when - processing <code class="Dv">ERASE</code> characters, followed by a forward - slash.</p> -<p class="Pp">If <code class="Dv">ECHOCTL</code> is set, the system echoes - control characters in a visible fashion using a caret followed by the - control character.</p> -<p class="Pp">If <code class="Dv">ALTWERASE</code> is set, the system uses an - alternative algorithm for determining what constitutes a word when - processing <code class="Dv">WERASE</code> characters (see - <code class="Dv">WERASE</code>).</p> -<p class="Pp">If <code class="Dv">ECHONL</code> and - <code class="Dv">ICANON</code> are set, the - ‘<code class="Li">\n</code>’ character echoes even if - <code class="Dv">ECHO</code> is not set.</p> -<p class="Pp">If <code class="Dv">ICANON</code> is set, canonical processing is - enabled. This enables the erase and kill edit functions, and the assembly of - input characters into lines delimited by <code class="Dv">NL</code>, - <code class="Dv">EOF</code>, and <code class="Dv">EOL</code>, as described - in <a class="Sx" href="#Canonical_Mode_Input_Processing">Canonical Mode - Input Processing</a>.</p> -<p class="Pp">If <code class="Dv">ICANON</code> is not set, read requests are - satisfied directly from the input queue. A read is not satisfied until at - least <code class="Dv">MIN</code> bytes have been received or the timeout - value <code class="Dv">TIME</code> expired between bytes. The time value - represents tenths of seconds. See - <a class="Sx" href="#Noncanonical_Mode_Input_Processing">Noncanonical Mode - Input Processing</a> for more details.</p> -<p class="Pp">If <code class="Dv">ISIG</code> is set, each input character is - checked against the special control characters <code class="Dv">INTR</code>, - <code class="Dv">QUIT</code>, and <code class="Dv">SUSP</code> (job control - only). If an input character matches one of these control characters, the - function associated with that character is performed. If - <code class="Dv">ISIG</code> is not set, no checking is done. Thus these - special input functions are possible only if <code class="Dv">ISIG</code> is - set.</p> -<p class="Pp">If <code class="Dv">IEXTEN</code> is set, implementation-defined - functions are recognized from the input data. How - <code class="Dv">IEXTEN</code> being set interacts with - <code class="Dv">ICANON</code>, <code class="Dv">ISIG</code>, - <code class="Dv">IXON</code>, or <code class="Dv">IXOFF</code> is - implementation defined. If <code class="Dv">IEXTEN</code> is not set, then - implementation-defined functions are not recognized, and the corresponding - input characters are not processed as described for - <code class="Dv">ICANON</code>, <code class="Dv">ISIG</code>, - <code class="Dv">IXON</code>, and <code class="Dv">IXOFF</code>.</p> -<p class="Pp">If <code class="Dv">NOFLSH</code> is set, the normal flush of the - input and output queues associated with the <code class="Dv">INTR</code>, - <code class="Dv">QUIT</code>, and <code class="Dv">SUSP</code> characters - are not be done.</p> -<p class="Pp">If <code class="Dv">TOSTOP</code> is set, the signal - <code class="Dv">SIGTTOU</code> 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 <code class="Dv">SIGTTOU</code> signals are excepted and allowed - to produce output and the <code class="Dv">SIGTTOU</code> signal is not - sent.</p> -<p class="Pp">If <code class="Dv">NOKERNINFO</code> is set, the kernel does not - produce a status message when processing <code class="Dv">STATUS</code> - characters (see <code class="Dv">STATUS</code>).</p> -</section> -<section class="Ss"> -<h2 class="Ss" id="Special_Control_Characters"><a class="permalink" href="#Special_Control_Characters">Special - Control Characters</a></h2> -<p class="Pp">The special control characters values are defined by the array - <var class="Fa">c_cc</var>. This table lists the array index, the - corresponding special character, and the system default value. For an - accurate list of the system defaults, consult the header file - <code class="In"><<a class="In">sys/ttydefaults.h</a>></code>.</p> -<p class="Pp"></p> -<table class="Bl-column Bd-indent Bl-compact"> - <tr id="Index"> - <td><a class="permalink" href="#Index"><i class="Em">Index Name</i></a></td> - <td>Special Character</td> - <td>Default Value</td> - </tr> - <tr id="VEOF"> - <td><a class="permalink" href="#VEOF"><code class="Dv">VEOF</code></a></td> - <td>EOF</td> - <td>^D</td> - </tr> - <tr id="VEOL"> - <td><a class="permalink" href="#VEOL"><code class="Dv">VEOL</code></a></td> - <td>EOL</td> - <td>_POSIX_VDISABLE</td> - </tr> - <tr id="VEOL2"> - <td><a class="permalink" href="#VEOL2"><code class="Dv">VEOL2</code></a></td> - <td>EOL2</td> - <td>_POSIX_VDISABLE</td> - </tr> - <tr id="VERASE"> - <td><a class="permalink" href="#VERASE"><code class="Dv">VERASE</code></a></td> - <td>ERASE</td> - <td>^? ‘<code class="Li">\177</code>’</td> - </tr> - <tr id="VWERASE"> - <td><a class="permalink" href="#VWERASE"><code class="Dv">VWERASE</code></a></td> - <td>WERASE</td> - <td>^W</td> - </tr> - <tr id="VKILL"> - <td><a class="permalink" href="#VKILL"><code class="Dv">VKILL</code></a></td> - <td>KILL</td> - <td>^U</td> - </tr> - <tr id="VREPRINT"> - <td><a class="permalink" href="#VREPRINT"><code class="Dv">VREPRINT</code></a></td> - <td>REPRINT</td> - <td>^R</td> - </tr> - <tr id="VINTR"> - <td><a class="permalink" href="#VINTR"><code class="Dv">VINTR</code></a></td> - <td>INTR</td> - <td>^C</td> - </tr> - <tr id="VQUIT"> - <td><a class="permalink" href="#VQUIT"><code class="Dv">VQUIT</code></a></td> - <td>QUIT</td> - <td>^\\ ‘<code class="Li">\34</code>’</td> - </tr> - <tr id="VSUSP"> - <td><a class="permalink" href="#VSUSP"><code class="Dv">VSUSP</code></a></td> - <td>SUSP</td> - <td>^Z</td> - </tr> - <tr id="VDSUSP"> - <td><a class="permalink" href="#VDSUSP"><code class="Dv">VDSUSP</code></a></td> - <td>DSUSP</td> - <td>^Y</td> - </tr> - <tr id="VSTART"> - <td><a class="permalink" href="#VSTART"><code class="Dv">VSTART</code></a></td> - <td>START</td> - <td>^Q</td> - </tr> - <tr id="VSTOP"> - <td><a class="permalink" href="#VSTOP"><code class="Dv">VSTOP</code></a></td> - <td>STOP</td> - <td>^S</td> - </tr> - <tr id="VLNEXT"> - <td><a class="permalink" href="#VLNEXT"><code class="Dv">VLNEXT</code></a></td> - <td>LNEXT</td> - <td>^V</td> - </tr> - <tr id="VDISCARD"> - <td><a class="permalink" href="#VDISCARD"><code class="Dv">VDISCARD</code></a></td> - <td>DISCARD</td> - <td>^O</td> - </tr> - <tr id="VMIN"> - <td><a class="permalink" href="#VMIN"><code class="Dv">VMIN</code></a></td> - <td>---</td> - <td>1</td> - </tr> - <tr id="VTIME"> - <td><a class="permalink" href="#VTIME"><code class="Dv">VTIME</code></a></td> - <td>---</td> - <td>0</td> - </tr> - <tr id="VSTATUS"> - <td><a class="permalink" href="#VSTATUS"><code class="Dv">VSTATUS</code></a></td> - <td>STATUS</td> - <td>^T</td> - </tr> -</table> -<p class="Pp">If the value of one of the changeable special control characters - (see <a class="Sx" href="#Special_Characters">Special Characters</a>) is - <code class="Dv">{_POSIX_VDISABLE}</code>, that function is disabled; that - is, no input data is recognized as the disabled special character. If - <code class="Dv">ICANON</code> is not set, the value of - <code class="Dv">{_POSIX_VDISABLE}</code> has no special meaning for the - <code class="Dv">VMIN</code> and <code class="Dv">VTIME</code> entries of - the <var class="Fa">c_cc</var> array.</p> -<p class="Pp" id="open~3">The initial values of the flags and control characters - after <a class="permalink" href="#open~3"><code class="Fn">open</code></a>() - is set according to the values in the header - <code class="In"><<a class="In">sys/ttydefaults.h</a>></code>.</p> -</section> -</section> -<section class="Sh"> -<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE - ALSO</a></h1> -<p class="Pp"><a class="Xr">stty(1)</a>, <a class="Xr">tcgetsid(3)</a>, - <a class="Xr">tcgetwinsize(3)</a>, <a class="Xr">tcsendbreak(3)</a>, - <a class="Xr">tcsetattr(3)</a>, <a class="Xr">tcsetsid(3)</a>, - <a class="Xr">tty(4)</a>, <a class="Xr">uart(4)</a>, - <a class="Xr">stack(9)</a></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="BUGS"><a class="permalink" href="#BUGS">BUGS</a></h1> -<p class="Pp">Before the Internet, serial ports were primarily used for inbound - connections from terminals, either directly or through modems, these days - serial ports are primarily used for outbound connections to devices, an - evolution which unfortunately has spread the relevant documentation over - three different manual pages: <a class="Xr">termios(4)</a>, - <a class="Xr">uart(4)</a> and <a class="Xr">tty(4)</a>.</p> -<p class="Pp"></p> -</section> -</div> -<table class="foot"> - <tr> - <td class="foot-date">January 14, 2026</td> - <td class="foot-os">FreeBSD 15.0</td> - </tr> -</table> |