termios(M)                    06 January 1993                     termios(M)


 Name

    termios - POSIX general terminal interface

 Description

    This entry discusses the POSIX termios extensions to the termio(M) inter-
    face. Only those functions not described in termio(M) are described here.

    Certain characters have special functions on input.  These functions and
    their default character values are summarized as follows:

    SUSP      (Unset by default) If the ISIG flag is enabled, receipt of the
              SUSP character causes a SIGTSTP signal to be sent to the
              current process group.  The SUSP character is discarded when
              processed.  It is often set to <Ctrl>z.

    Several library functions apply to terminal files.  The primary calls use
    the following structure, defined in the file <termios.h>:

       #define NCCS    13
       struct termios {
           tcflag_t      c_iflag;     /* input modes */
           tcflag_t      c_oflag;     /* output modes */
           tcflag_t      c_cflag;     /* control modes */
           tcflag_t      c_lflag;     /* local (line discipline) modes */
           char          c_line;      /* line discipline */
           cc_t          c_cc[NCCS];  /* control chars */
           char          c_ispeed;    /* input baud rate */
           char          c_ospeed;    /* output baud rate */
       };

    The additional special control characters defined by the array ccc.
    are:

       10      VSUSP   NUL
       11      VSTART  DC1
       12      VSTOP   DC3

    The following additional line discipline (0) functions are available in
    the clflag field:

       IEXTEN  0000400 enable extended functions
       TOSTOP  0001000 SIGTTOU on background output

    If IEXTEN is set, additional non-POSIX functions are recognized. This is
    the default. If IEXTEN is not set, the modes ICANON, ISIG, IXON, and
    IXOFF are assumed.

    If TOSTOP is set, the signal SIGTTOU is sent to the process group of a
    process that tries to write to its controlling terminal if it is not the
    foreground process group.  By default, this signal stops the members of
    the process group.  If TOSTOP is not set, the output generated by the
    process is output to the current output stream.

    The associated library functions are found in tcattr(S) and tcflow(S).

 Files

    /dev/tty
    /dev/tty*
    /dev/console

 See also

    ioctl(S), signal(S), stty(C), tcattr(S), tcflow(S), termio(M) and tty(M).

 Standards conformance

    termios is conformant with:

    IEEE POSIX Std 1003.1-1990 System Application Program Interface (API) [C
    Language] (ISO/IEC 9945-1);
    and X/Open Portability Guide, Issue 3, 1989.

 Value added

    termios is an extension of AT&T System V provided by The Santa Cruz
    Operation, Inc.