NAME

       FIONREAD, TIOCINQ, TIOCOUTQ, TCFLSH, TIOCSERGETLSR - buffer count and flushing

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <asm/termbits.h>  /* Definition of constants */
       #include <sys/ioctl.h>

       int ioctl(int fd, FIONREAD, int *argp);
       int ioctl(int fd, TIOCINQ, int *argp);
       int ioctl(int fd, TIOCOUTQ, int *argp);
       int ioctl(int fd, TCFLSH, int arg);
       int ioctl(int fd, FIONREAD, int *argp);

DESCRIPTION

       FIONREAD
              Get the number of bytes in the input buffer.

       TIOCINQ
              Same as FIONREAD.

       TIOCOUTQ
              Get the number of bytes in the output buffer.

       TCFLSH Equivalent to tcflush(fd, arg).

              See tcflush(3) for the argument values TCIFLUSH, TCOFLUSH, TCIOFLUSH.

       TIOCSERGETLSR
              Get  line  status  register.  Status register has TIOCSER_TEMT bit set when output buffer is empty
              and also hardware transmitter is physically empty.

              Does not have to be supported by all serial tty drivers.

              tcdrain(3) does not wait and returns immediately when TIOCSER_TEMT bit is set.

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned, and errno is set to indicate the error.

SEE ALSO

       ioctl(2), ioctl_tty(2), tcflush(3), termios(3)

Linux man-pages 6.9.1                              2024-06-13                                   FIONREAD(2const)