1 .\" Hey Emacs! This file is -*- nroff -*- source.
3 .\" Copyright (c) 1993 Michael Haardt
5 .\" Fri Apr 2 11:32:09 MET DST 1993
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24 .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
27 .\" Modified 1993-07-24 by Rik Faith <faith@cs.unc.edu>
28 .\" Modified 1995-02-25 by Jim Van Zandt <jrv@vanzandt.mv.com>
29 .\" Modified 1995-09-02 by Jim Van Zandt <jrv@vanzandt.mv.com>
30 .\" moved to man3, aeb, 950919
31 .\" Modified 2001-09-22 by Michael Kerrisk <mtk.manpages@gmail.com>
32 .\" Modified 2001-12-17, aeb
33 .\" Modified 2004-10-31, aeb
35 .\" Added .SS headers to give some structure to this page; and a
36 .\" small amount of reordering.
37 .\" Added a section on canonical and non-canonical mode.
38 .\" Enhanced the discussion of "raw" mode for cfmakeraw().
41 .TH TERMIOS 3 2007-11-26 "Linux" "Linux Programmer's Manual"
43 termios, tcgetattr, tcsetattr, tcsendbreak, tcdrain, tcflush, tcflow,
44 cfmakeraw, cfgetospeed, cfgetispeed, cfsetispeed, cfsetospeed, cfsetspeed \-
45 get and set terminal attributes, line control, get and set baud rate
48 .B #include <termios.h>
50 .B #include <unistd.h>
52 .BI "int tcgetattr(int " fd ", struct termios *" termios_p );
54 .BI "int tcsetattr(int " fd ", int " optional_actions ,
55 .BI " const struct termios *" termios_p );
57 .BI "int tcsendbreak(int " fd ", int " duration );
59 .BI "int tcdrain(int " fd );
61 .BI "int tcflush(int " fd ", int " queue_selector );
63 .BI "int tcflow(int " fd ", int " action );
65 .BI "void cfmakeraw(struct termios *" termios_p );
67 .BI "speed_t cfgetispeed(const struct termios *" termios_p );
69 .BI "speed_t cfgetospeed(const struct termios *" termios_p );
71 .BI "int cfsetispeed(struct termios *" termios_p ", speed_t " speed );
73 .BI "int cfsetospeed(struct termios *" termios_p ", speed_t " speed );
75 .BI "int cfsetspeed(struct termios *" termios_p ", speed_t " speed );
79 Feature Test Macro Requirements for glibc (see
80 .BR feature_test_macros (7)):
87 The termios functions describe a general terminal interface that is
88 provided to control asynchronous communications ports.
89 .SS "The termios structure"
91 Many of the functions described here have a \fItermios_p\fP argument
92 that is a pointer to a \fItermios\fP structure.
93 This structure contains at least the following members:
97 tcflag_t c_iflag; /* input modes */
98 tcflag_t c_oflag; /* output modes */
99 tcflag_t c_cflag; /* control modes */
100 tcflag_t c_lflag; /* local modes */
101 cc_t c_cc[NCCS]; /* control chars */
105 The values that may be assigned to these fields are described below.
106 In the case of the first four bit-mask fields,
107 the definitions of some of the associated flags that may be set are
108 only exposed if a specific feature test macro (see
109 .BR feature_test_macros (7))
110 is defined, as noted in brackets ("[]").
112 In the descriptions below, "not in POSIX" means that the
113 value is not specified in POSIX.1-2001,
114 and "XSI" means that the value is specified in POSIX.1-2001
115 as part of the XSI extension.
117 \fIc_iflag\fP flag constants:
120 Ignore BREAK condition on input.
123 If \fBIGNBRK\fP is set, a BREAK is ignored.
125 but \fBBRKINT\fP is set, then a BREAK causes the input and output
126 queues to be flushed, and if the terminal is the controlling
127 terminal of a foreground process group, it will cause a
128 \fBSIGINT\fP to be sent to this foreground process group.
129 When neither \fBIGNBRK\fP nor \fBBRKINT\fP are set, a BREAK
130 reads as a null byte ('\\0'), except when \fBPARMRK\fP is set,
131 in which case it reads as the sequence \\377 \\0 \\0.
134 Ignore framing errors and parity errors.
137 If \fBIGNPAR\fP is not set, prefix a character with a parity error or
138 framing error with \\377 \\0.
139 If neither \fBIGNPAR\fP nor \fBPARMRK\fP
140 is set, read a character with a parity error or framing error
144 Enable input parity checking.
147 Strip off eighth bit.
150 Translate NL to CR on input.
153 Ignore carriage return on input.
156 Translate carriage return to newline on input (unless \fBIGNCR\fP is set).
159 (not in POSIX) Map uppercase characters to lowercase on input.
162 Enable XON/XOFF flow control on output.
165 (XSI) Typing any character will restart stopped output.
166 (The default is to allow just the START character to restart output.)
169 Enable XON/XOFF flow control on input.
172 (not in POSIX) Ring bell when input queue is full.
173 Linux does not implement this bit, and acts as if it is always set.
175 .BR IUTF8 " (since Linux 2.6.4)"
176 (not in POSIX) Input is UTF8;
177 this allows character-erase to be correctly performed in cooked mode.
179 \fIc_oflag\fP flag constants defined in POSIX.1:
182 Enable implementation-defined output processing.
184 The remaining \fIc_oflag\fP flag constants are defined in POSIX.1-2001,
185 unless marked otherwise.
188 (not in POSIX) Map lowercase characters to uppercase on output.
191 (XSI) Map NL to CR-NL on output.
194 Map CR to NL on output.
197 Don't output CR at column 0.
203 Send fill characters for a delay, rather than using a timed delay.
206 (not in POSIX) Fill character is ASCII DEL (0177).
207 If unset, fill character is ASCII NUL ('\\0').
208 (Not implemented on Linux.)
212 Values are \fBNL0\fP and \fBNL1\fP.
221 Carriage return delay mask.
222 Values are \fBCR0\fP, \fBCR1\fP, \fBCR2\fP, or \fBCR3\fP.
231 Horizontal tab delay mask.
232 Values are \fBTAB0\fP, \fBTAB1\fP, \fBTAB2\fP, \fBTAB3\fP (or \fBXTABS\fP).
233 A value of TAB3, that is, XTABS, expands tabs to spaces
234 (with tab stops every eight columns).
243 Backspace delay mask.
244 Values are \fBBS0\fP or \fBBS1\fP.
245 (Has never been implemented.)
254 Vertical tab delay mask.
255 Values are \fBVT0\fP or \fBVT1\fP.
258 Form feed delay mask.
259 Values are \fBFF0\fP or \fBFF1\fP.
267 \fIc_cflag\fP flag constants:
270 (not in POSIX) Baud speed mask (4+1 bits).
277 (not in POSIX) Extra baud speed mask (1 bit), included in
284 (POSIX says that the baud speed is stored in the
286 structure without specifying where precisely, and provides
291 Some systems use bits selected by
295 other systems use separate fields, for example,
302 Values are \fBCS5\fP, \fBCS6\fP, \fBCS7\fP, or \fBCS8\fP.
305 Set two stop bits, rather than one.
311 Enable parity generation on output and parity checking for input.
314 If set, then parity for input and output is odd;
315 otherwise even parity is used.
318 Lower modem control lines after last process closes the device (hang up).
321 Ignore modem control lines.
324 (not in POSIX) Block output from a non-current shell layer.
325 For use by \fBshl\fP (shell layers). (Not implemented on Linux.)
328 (not in POSIX) Mask for input speeds.
332 the same as the values for the
341 (Not implemented on Linux.)
345 Use "stick" (mark/space) parity (supported on certain serial
348 is set, the parity bit is always 1; if
350 is not set, then the parity bit is always 0).
357 (not in POSIX) Enable RTS/CTS (hardware) flow control.
363 \fIc_lflag\fP flag constants:
366 When any of the characters INTR, QUIT, SUSP, or DSUSP are received,
367 generate the corresponding signal.
370 Enable canonical mode (described below).
373 (not in POSIX; not supported under Linux)
374 If \fBICANON\fP is also set, terminal is uppercase only.
375 Input is converted to lowercase, except for characters preceded by \\.
376 On output, uppercase characters are preceded by \\ and lowercase
377 characters are converted to uppercase.
378 [requires _BSD_SOURCE or _SVID_SOURCE or _XOPEN_SOURCE]
379 .\" glibc is probably now wrong to allow
386 Echo input characters.
389 If \fBICANON\fP is also set, the ERASE character erases the preceding
390 input character, and WERASE erases the preceding word.
393 If \fBICANON\fP is also set, the KILL character erases the current line.
396 If \fBICANON\fP is also set, echo the NL character even if ECHO is not set.
399 (not in POSIX) If \fBECHO\fP is also set, ASCII control signals other than
400 TAB, NL, START, and STOP are echoed as ^X, where X is the character with
401 ASCII code 0x40 greater than the control signal.
402 For example, character
403 0x08 (BS) is echoed as ^H.
410 (not in POSIX) If \fBICANON\fP and \fBIECHO\fP are also set, characters
411 are printed as they are being erased.
418 (not in POSIX) If \fBICANON\fP is also set, KILL is echoed by erasing
419 each character on the line, as specified by \fBECHOE\fP and \fBECHOPRT\fP.
426 (not in POSIX) Echo only when a process is reading.
427 (Not implemented on Linux.)
430 (not in POSIX; not supported under Linux)
431 Output is being flushed.
432 This flag is toggled by typing
433 the DISCARD character.
440 Disable flushing the input and output queues when generating the
446 .\" Stevens lets SIGSUSP only flush the input queue
451 signal to the process group of a background process
452 which tries to write to its controlling terminal.
455 (not in POSIX; not supported under Linux)
456 All characters in the input queue are reprinted when
457 the next character is read.
459 handles typeahead this way.)
466 Enable implementation-defined input processing.
467 This flag, as well as \fBICANON\fP must be enabled for the
468 special characters EOL2, LNEXT, REPRINT, WERASE to be interpreted,
469 and for the \fBIUCLC\fP flag to be effective.
471 The \fIc_cc\fP array defines the special control characters.
472 The symbolic indices (initial values) and meaning are:
475 (003, ETX, Ctrl-C, or also 0177, DEL, rubout)
482 is set, and then not passed as input.
492 is set, and then not passed as input.
495 (0177, DEL, rubout, or 010, BS, Ctrl-H, or also #)
497 This erases the previous not-yet-erased character,
498 but does not erase past EOF or beginning-of-line.
501 is set, and then not passed as input.
504 (025, NAK, Ctrl-U, or Ctrl-X, or also @)
506 This erases the input since the last EOF or beginning-of-line.
509 is set, and then not passed as input.
513 End-of-file character.
514 More precisely: this character causes the pending tty buffer to be sent
515 to the waiting user program without waiting for end-of-line.
516 If it is the first character of the line, the
518 in the user program returns 0, which signifies end-of-file.
521 is set, and then not passed as input.
524 Minimum number of characters for non-canonical read.
528 Additional end-of-line character.
534 Timeout in deciseconds for non-canonical read.
537 (not in POSIX; 0, NUL)
538 Yet another end-of-line character.
544 (not in POSIX; not supported under Linux; 0, NUL)
546 (Used by \fBshl\fP only.)
551 Restarts output stopped by the Stop character.
554 is set, and then not passed as input.
559 Stop output until Start character typed.
562 is set, and then not passed as input.
572 is set, and then not passed as input.
575 (not in POSIX; not supported under Linux; 031, EM, Ctrl-Y)
576 Delayed suspend character:
579 signal when the character is read by the user program.
584 are set, and the system supports
585 job control, and then not passed as input.
588 (not in POSIX; 026, SYN, Ctrl-V)
590 Quotes the next input character, depriving it of
591 a possible special meaning.
594 is set, and then not passed as input.
597 (not in POSIX; 027, ETB, Ctrl-W)
603 are set, and then not passed as input.
606 (not in POSIX; 022, DC2, Ctrl-R)
607 Reprint unread characters.
612 are set, and then not passed as input.
615 (not in POSIX; not supported under Linux; 017, SI, Ctrl-O)
616 Toggle: start/stop discarding pending output.
619 is set, and then not passed as input.
622 (not in POSIX; not supported under Linux;
623 status request: 024, DC4, Ctrl-T).
625 These symbolic subscript values are all different, except that
628 may have the same value as
632 In non-canonical mode the special character meaning is replaced
633 by the timeout meaning.
634 For an explanation of
638 see the description of
639 non-canonical mode below.
640 .SS "Retrieving and changing terminal settings"
643 gets the parameters associated with the object referred by \fIfd\fP and
644 stores them in the \fItermios\fP structure referenced by
646 This function may be invoked from a background process;
647 however, the terminal attributes may be subsequently changed by a
651 sets the parameters associated with the terminal (unless support is
652 required from the underlying hardware that is not available) from the
653 \fItermios\fP structure referred to by \fItermios_p\fP.
654 \fIoptional_actions\fP specifies when the changes take effect:
656 the change occurs immediately.
658 the change occurs after all output written to
660 has been transmitted.
661 This function should be used when changing
662 parameters that affect output.
664 the change occurs after all output written to the object referred by
666 has been transmitted, and all input that has been received but not read
667 will be discarded before the change is made.
668 .SS "Canonical and non-canonical mode"
673 determines whether the terminal is operating in canonical mode
685 Input is made available line by line.
686 An input line is available when one of the line delimiters
687 is typed (NL, EOL, EOL2; or EOF at the start of line).
688 Except in the case of EOF, the line delimiter is included
689 in the buffer returned by
692 Line editing is enabled (ERASE, KILL;
695 flag is set: WERASE, REPRINT, LNEXT).
698 returns at most one line of input; if the
700 requested fewer bytes than are available in the current line of input,
701 then only as many bytes as requested are read,
702 and the remaining characters will be available for a future
705 In non-canonical mode input is available immediately (without
706 the user having to type a line-delimiter character),
707 and line editing is disabled.
712 determine the circumstances in which a
714 completes; there are four distinct cases:
717 If data is available,
719 returns immediately, with the lesser of the number of bytes
720 available, or the number of bytes requested.
721 If no data is available,
727 blocks until the lesser of MIN bytes or the number of bytes requested
728 are available, and returns the lesser of these two values.
731 TIME specifies the limit for a timer in tenths of a second.
732 The timer is started when
736 returns either when at least one byte of data is available,
737 or when the timer expires.
738 If the timer expires without any input becoming available,
743 TIME specifies the limit for a timer in tenths of a second.
744 Once an initial byte of input becomes available,
745 the timer is restarted after each further byte is received.
747 returns either when the lesser of the number of bytes requested or
748 MIN byte have been read,
749 or when the inter-byte timeout expires.
750 Because the timer is only started after the initial byte
751 becomes available, at least one byte will be read.
755 sets the terminal to something like the
756 "raw" mode of the old Version 7 terminal driver:
757 input is available character by character,
758 echoing is disabled, and all special processing of
759 terminal input and output characters is disabled.
760 The terminal attributes are set as follows:
763 termios_p\->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
764 | INLCR | IGNCR | ICRNL | IXON);
765 termios_p\->c_oflag &= ~OPOST;
766 termios_p\->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
767 termios_p\->c_cflag &= ~(CSIZE | PARENB);
768 termios_p\->c_cflag |= CS8;
773 transmits a continuous stream of zero-valued bits for a specific
774 duration, if the terminal is using asynchronous serial data
776 If \fIduration\fP is zero, it transmits zero-valued bits
777 for at least 0.25 seconds, and not more that 0.5 seconds.
778 If \fIduration\fP is not zero, it sends zero-valued bits for some
779 implementation-defined length of time.
781 If the terminal is not using asynchronous serial data transmission,
783 returns without taking any action.
786 waits until all output written to the object referred to by
788 has been transmitted.
791 discards data written to the object referred to by
793 but not transmitted, or data received but not read, depending on the
797 flushes data received but not read.
799 flushes data written but not transmitted.
801 flushes both data received but not read, and data written but not
805 suspends transmission or reception of data on the object referred to by
807 depending on the value of
812 restarts suspended output.
814 transmits a STOP character, which stops the terminal device from
815 transmitting data to the system.
817 transmits a START character, which starts the terminal device
818 transmitting data to the system.
820 The default on open of a terminal file is that neither its input nor its
823 The baud rate functions are provided for getting and setting the values
824 of the input and output baud rates in the \fItermios\fP structure.
825 The new values do not take effect
828 is successfully called.
830 Setting the speed to \fBB0\fP instructs the modem to "hang up".
831 The actual bit rate corresponding to \fBB38400\fP may be altered with
834 The input and output baud rates are stored in the \fItermios\fP
838 returns the output baud rate stored in the \fItermios\fP structure
843 sets the output baud rate stored in the \fItermios\fP structure pointed
844 to by \fItermios_p\fP to \fIspeed\fP, which must be one of these constants:
870 The zero baud rate, \fBB0\fP,
871 is used to terminate the connection.
872 If B0 is specified, the modem control lines shall no longer be asserted.
873 Normally, this will disconnect the line.
874 \fBCBAUDEX\fP is a mask
875 for the speeds beyond those defined in POSIX.1 (57600 and above).
876 Thus, \fBB57600\fP & \fBCBAUDEX\fP is non-zero.
879 returns the input baud rate stored in the \fItermios\fP structure.
882 sets the input baud rate stored in the \fItermios\fP structure to
884 which must be specified as one of the \fBBnnn\fP constants listed above for
886 If the input baud rate is set to zero, the input baud rate will be
887 equal to the output baud rate.
890 is a 4.4BSD extension.
891 It takes the same arguments as
893 and sets both input and output speed.
897 returns the input baud rate stored in the
902 returns the output baud rate stored in the \fItermios\fP structure.
904 All other functions return:
910 to indicate the error.
914 returns success if \fIany\fP of the requested changes could be
915 successfully carried out.
916 Therefore, when making multiple changes
917 it may be necessary to follow this call with a further call to
919 to check that all changes have been performed successfully.
932 are specified in POSIX.1-2001.
937 are non-standard, but available on the BSDs.
939 Unix V7 and several later systems have a list of baud rates
940 where after the fourteen values B0, ..., B9600 one finds the
941 two constants EXTA, EXTB ("External A" and "External B").
942 Many systems extend the list with much higher baud rates.
944 The effect of a non-zero \fIduration\fP with
947 SunOS specifies a break of
949 seconds, where \fIN\fP is at least 0.25, and not more than 0.5.
950 Linux, AIX, DU, Tru64 send a break of
953 FreeBSD and NetBSD and HP-UX and MacOS ignore the value of
955 Under Solaris and Unixware,
961 .\" libc4 until 4.7.5, glibc for sysv: EINVAL for duration > 0.
962 .\" libc4.7.6, libc5, glibc for unix: duration in ms.
963 .\" glibc for bsd: duration in us
964 .\" glibc for sunos4: ignore duration
967 .BR console_ioctl (4),
projects / thirdparty / man-pages.git / blob