tcsendbreak(3) — Linux manual page

tcsendbreak(3)           Library Functions Manual          tcsendbreak(3)

NAME         top

       tcsendbreak - send a continuous stream of zero-valued bits

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <termios.h>

       int tcsendbreak(int fd, int duration);

DESCRIPTION         top

       tcsendbreak() transmits a continuous stream of zero-valued bits
       for a specific duration, if the terminal is using asynchronous
       serial data transmission.

       If duration is zero, it transmits zero-valued bits for at least
       0.25 seconds, and not more than 0.5 seconds.

       If duration is not zero, it sends zero-valued bits for some
       implementation-defined length of time.

       If the terminal is not using asynchronous serial data
       transmission, tcsendbreak() returns without taking any action.

RETURN VALUE         top

       0      on success.

       -1     on failure and set errno to indicate the error.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                            │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │ tcsendbreak()                        │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

VERSIONS         top

       The effect of a nonzero duration with tcsendbreak() varies.  SunOS
       specifies a break of duration * N seconds, where N is at least
       0.25, and not more than 0.5.  Linux, AIX, DU, Tru64 send a break
       of duration milliseconds.  FreeBSD and NetBSD and HP-UX and MacOS
       ignore the value of duration.  Under Solaris and UnixWare,
       tcsendbreak() with nonzero duration behaves like tcdrain(3).

STANDARDS         top

       POSIX.1-2008.

HISTORY         top

       POSIX.1-2001.

SEE ALSO         top

       tcdrain(3), tcflush(3), tcflow(3), termios(7)

COLOPHON         top

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.19.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2026-09-09.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.19            2026-07-02                 tcsendbreak(3)

Pages that refer to this page: tcdrain(3),  tcflow(3),  tcflush(3),  signal-safety(7),  termios(7)

HTML rendering created 2026-09-09 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.