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PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       termios.h — define values for termios

SYNOPSIS

       #include <termios.h>

DESCRIPTION

       The  <termios.h>  header shall contain the definitions used by the terminal I/O interfaces
       (see Chapter 11, General Terminal Interface for the structures and names defined).

   The termios Structure
       The <termios.h> header shall define the following data types through typedef:

       cc_t        Used for terminal special characters.

       speed_t     Used for terminal baud rates.

       tcflag_t    Used for terminal modes.

       The above types shall be all unsigned integer types.

       The implementation shall support one or more programming environments in which the  widths
       of  cc_t,  speed_t, and tcflag_t are no greater than the width of type long.  The names of
       these programming environments can be obtained using the confstr() function or the getconf
       utility.

       The  <termios.h>  header  shall define the termios structure, which shall include at least
       the following members:

           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 characters.

       The <termios.h> header shall define the following symbolic constant:

       NCCS        Size of the array c_cc for control characters.

       The <termios.h> header shall define the following symbolic constants for use as subscripts
       for the array c_cc:

                        ┌────────────────────────────────────┬──────────────────┐
                        │          Subscript Usage           │                  │
                        │Canonical Mode   Non-Canonical ModeDescription    │
                        ├───────────────┬────────────────────┼──────────────────┤
                        │VEOF           │                    │ EOF character.   │
                        │VEOL           │                    │ EOL character.   │
                        │VERASE         │                    │ ERASE character. │
                        │VINTR          │ VINTR              │ INTR character.  │
                        │VKILL          │                    │ KILL character.  │
                        │               │ VMIN               │ MIN value.       │
                        │VQUIT          │ VQUIT              │ QUIT character.  │
                        │VSTART         │ VSTART             │ START character. │
                        │VSTOP          │ VSTOP              │ STOP character.  │
                        │VSUSP          │ VSUSP              │ SUSP character.  │
                        │               │ VTIME              │ TIME value.      │
                        └───────────────┴────────────────────┴──────────────────┘
       The  subscript  values shall be suitable for use in #if preprocessing directives and shall
       be distinct, except that the VMIN and VTIME subscripts may have the  same  values  as  the
       VEOF and VEOL subscripts, respectively.

   Input Modes
       The  <termios.h>  header shall define the following symbolic constants for use as flags in
       the c_iflag field. The c_iflag field describes the basic terminal input control.

       BRKINT      Signal interrupt on break.

       ICRNL       Map CR to NL on input.

       IGNBRK      Ignore break condition.

       IGNCR       Ignore CR.

       IGNPAR      Ignore characters with parity errors.

       INLCR       Map NL to CR on input.

       INPCK       Enable input parity check.

       ISTRIP      Strip character.

       IXANY       Enable any character to restart output.

       IXOFF       Enable start/stop input control.

       IXON        Enable start/stop output control.

       PARMRK      Mark parity errors.

   Output Modes
       The <termios.h> header shall define the following symbolic constants for use as  flags  in
       the c_oflag field. The c_oflag field specifies the system treatment of output.

       OPOST       Post-process output.

       ONLCR       Map NL to CR-NL on output.

       OCRNL       Map CR to NL on output.

       ONOCR       No CR output at column 0.

       ONLRET      NL performs CR function.

       OFDEL       Fill is DEL.

       OFILL       Use fill characters for delay.

       NLDLY       Select newline delays:

                   NL0     Newline type 0.

                   NL1     Newline type 1.

       CRDLY       Select carriage-return delays:

                   CR0     Carriage-return delay type 0.

                   CR1     Carriage-return delay type 1.

                   CR2     Carriage-return delay type 2.

                   CR3     Carriage-return delay type 3.

       TABDLY      Select horizontal-tab delays:

                   TAB0    Horizontal-tab delay type 0.

                   TAB1    Horizontal-tab delay type 1.

                   TAB2    Horizontal-tab delay type 2.

                   TAB3    Expand tabs to spaces.

       BSDLY       Select backspace delays:

                   BS0     Backspace-delay type 0.

                   BS1     Backspace-delay type 1.

       VTDLY       Select vertical-tab delays:

                   VT0     Vertical-tab delay type 0.

                   VT1     Vertical-tab delay type 1.

       FFDLY       Select form-feed delays:

                   FF0     Form-feed delay type 0.

                   FF1     Form-feed delay type 1.

   Baud Rate Selection
       The  <termios.h> header shall define the following symbolic constants for use as values of
       objects of type speed_t.

       The input and output baud rates are stored in the termios structure. These are  the  valid
       values  for  objects  of  type  speed_t.   Not  all  baud  rates  need be supported by the
       underlying hardware.

       B0          Hang up

       B50         50 baud

       B75         75 baud

       B110        110 baud

       B134        134.5 baud

       B150        150 baud

       B200        200 baud

       B300        300 baud

       B600        600 baud

       B1200       1200 baud

       B1800       1800 baud

       B2400       2400 baud

       B4800       4800 baud

       B9600       9600 baud

       B19200      19200 baud

       B38400      38400 baud

   Control Modes
       The <termios.h> header shall define the following symbolic constants for use as  flags  in
       the  c_cflag  field. The c_cflag field describes the hardware control of the terminal; not
       all values specified are required to be supported by the underlying hardware.

       CSIZE       Character size:

                   CS5     5 bits

                   CS6     6 bits

                   CS7     7 bits

                   CS8     8 bits

       CSTOPB      Send two stop bits, else one.

       CREAD       Enable receiver.

       PARENB      Parity enable.

       PARODD      Odd parity, else even.

       HUPCL       Hang up on last close.

       CLOCAL      Ignore modem status lines.

       The implementation shall support the functionality associated with the symbols  CS7,  CS8,
       CSTOPB, PARODD, and PARENB.

   Local Modes
       The  <termios.h>  header shall define the following symbolic constants for use as flags in
       the c_lflag field. The c_lflag field of the argument structure is used to control  various
       terminal functions.

       ECHO        Enable echo.

       ECHOE       Echo erase character as error-correcting backspace.

       ECHOK       Echo KILL.

       ECHONL      Echo NL.

       ICANON      Canonical input (erase and kill processing).

       IEXTEN      Enable extended input character processing.

       ISIG        Enable signals.

       NOFLSH      Disable flush after interrupt or quit.

       TOSTOP      Send SIGTTOU for background output.

   Attribute Selection
       The  <termios.h>  header  shall  define  the  following  symbolic  constants  for use with
       tcsetattr():

       TCSANOW     Change attributes immediately.

       TCSADRAIN   Change attributes when output has drained.

       TCSAFLUSH   Change attributes when output has drained; also flush pending input.

   Line Control
       The <termios.h> header  shall  define  the  following  symbolic  constants  for  use  with
       tcflush():

       TCIFLUSH    Flush pending input.

       TCIOFLUSH   Flush both pending input and untransmitted output.

       TCOFLUSH    Flush untransmitted output.

       The  <termios.h>  header  shall  define  the  following  symbolic  constants  for use with
       tcflow():

       TCIOFF      Transmit a STOP character, intended to suspend input data.

       TCION       Transmit a START character, intended to restart input data.

       TCOOFF      Suspend output.

       TCOON       Restart output.

       The <termios.h> header shall define the pid_t type as described in <sys/types.h>.

       The following shall be declared as functions and may also be defined as  macros.  Function
       prototypes shall be provided.

           speed_t cfgetispeed(const struct termios *);
           speed_t cfgetospeed(const struct termios *);
           int     cfsetispeed(struct termios *, speed_t);
           int     cfsetospeed(struct termios *, speed_t);
           int     tcdrain(int);
           int     tcflow(int, int);
           int     tcflush(int, int);
           int     tcgetattr(int, struct termios *);
           pid_t   tcgetsid(int);
           int     tcsendbreak(int, int);
           int     tcsetattr(int, int, const struct termios *);

       The following sections are informative.

APPLICATION USAGE

       The  following names are reserved for XSI-conformant systems to use as an extension to the
       above; therefore strictly conforming applications shall not use them:

       CBAUD      EXTB       VDSUSP
       DEFECHO    FLUSHO     VLNEXT
       ECHOCTL    LOBLK      VREPRINT
       ECHOKE     PENDIN     VSTATUS
       ECHOPRT    SWTCH      VWERASE
       EXTA       VDISCARD

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <sys_types.h>

       The System Interfaces volume of POSIX.1‐2017, cfgetispeed(), cfgetospeed(), cfsetispeed(),
       cfsetospeed(),   confstr(),   tcdrain(),  tcflow(),  tcflush(),  tcgetattr(),  tcgetsid(),
       tcsendbreak(), tcsetattr()

       The Shell and Utilities volume of POSIX.1‐2017, Chapter 11,  General  Terminal  Interface,
       getconf

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by
       the Institute of Electrical and Electronics Engineers, Inc and The  Open  Group.   In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .