tcflow(3)                  Library Functions Manual                  tcflow(3)

NAME
       tcflow - suspect transmission or reception of data

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <termios.h>

       int tcflow(int fd, int action);

DESCRIPTION
       tcflow() suspends transmission or reception of data on the object
       referred to by fd, depending on the value of action:

       TCOOFF suspends output.

       TCOON  restarts suspended output.

       TCIOFF transmits a STOP character, which stops the terminal device from
              transmitting data to the system.

       TCION  transmits a START character, which starts the terminal device
              transmitting data to the system.

       The default on open of a terminal file is that neither its input nor
       its output is suspended.

RETURN VALUE
       0      on success.

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

ATTRIBUTES
       For an explanation of the terms used in this section, see
       attributes(7).

       +--------------------------------------------+---------------+---------+
       |Interface                                   | Attribute     | Value   |
       +--------------------------------------------+---------------+---------+
       |tcflow ()                                   | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       POSIX.1-2008.

HISTORY
       POSIX.1-2001.

SEE ALSO
       tcsendbreak(3), tcdrain(3), tcflush(3), termios(7)

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