tcsetattr(3)               Library Functions Manual               tcsetattr(3)

NAME
       tcgetattr, tcsetattr - get and set terminal attributes

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <termios.h>

       int tcgetattr(int fd, struct termios *termios_p);
       int tcsetattr(int fd, int optional_actions,
                     const struct termios *termios_p);

DESCRIPTION
       tcgetattr() gets the parameters associated with the object referred by
       fd, and stores them in the termios structure referenced by termios_p.
       This function may be invoked from a background process; however, the
       terminal attributes may be subsequently changed by a foreground
       process.

       tcsetattr() sets the parameters associated with the terminal (unless
       support is required from the underlying hardware that is not available)
       from the termios structure referred to by termios_p.  optional_actions
       specifies when the changes take effect:

       TCSANOW
              the change occurs immediately.

       TCSADRAIN
              the change occurs after all output written to fd has been
              transmitted.  This option should be used when changing
              parameters that affect output.

       TCSAFLUSH
              the change occurs after all output written to the object
              referred by fd has been transmitted, and all input that has been
              received but not read will be discarded before the change is
              made.

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   |
       +--------------------------------------------+---------------+---------+
       |tcgetattr (), tcsetattr ()                  | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       POSIX.1-2008.

HISTORY
       POSIX.1-2001.

CAVEATS
       tcsetattr() returns success if any of the requested changes could be
       successfully carried out.  Therefore, when making multiple changes, it
       may be necessary to follow this call with a further call to tcgetattr()
       to check that all changes have been performed successfully.

SEE ALSO
       termios(3type), termios(7)

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