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)