FIONREAD(2const)

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)