tcflush(3)                 Library Functions Manual                 tcflush(3)

NAME
       tcflush - discard pending data

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <termios.h>

       int tcflush(int fd, int queue_selector);

DESCRIPTION
       tcflush() discards data written to the object referred to by fd but not
       transmitted, or data received but not read, depending on the value of
       queue_selector:

       TCIFLUSH
              flushes data received but not read.

       TCOFLUSH
              flushes data written but not transmitted.

       TCIOFLUSH
              flushes both data received but not read, and data written but
              not transmitted.

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   |
       +--------------------------------------------+---------------+---------+
       |tcflush ()                                  | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       POSIX.1-2008.

HISTORY
       POSIX.1-2001.

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

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