tcdrain(3)                 Library Functions Manual                 tcdrain(3)

NAME
       tcdrain - block until output is transmitted

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <termios.h>

       int tcdrain(int fd);

DESCRIPTION
       tcdrain() waits until all output written to the object referred to by
       fd has been 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   |
       +--------------------------------------------+---------------+---------+
       |tcdrain ()                                  | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       POSIX.1-2008.

HISTORY
       POSIX.1-2001.

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

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