FIONREAD(2const) - Linux manual page (original) (raw)

FIONREAD(2const) FIONREAD(2const)

NAME top

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

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#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_**, TIOCSERGETLSR, int ***_argp_**);**

DESCRIPTION top

   **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)](../man3/tcflush.3.html) 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)](../man3/tcdrain.3.html) does not wait and returns immediately when
          **TIOCSER_TEMT** bit is set.

RETURN VALUE top

   On success, 0 is returned.  On error, -1 is returned, and _[errno](../man3/errno.3.html)_ is
   set to indicate the error.

SEE ALSO top

   [ioctl(2)](../man2/ioctl.2.html), [ioctl_tty(2)](../man2/ioctl%5Ftty.2.html), [tcflush(3)](../man3/tcflush.3.html), [termios(3)](../man3/termios.3.html)

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Linux man-pages 6.10 2024-07-23 FIONREAD(2const)

Pages that refer to this page:ioctl_tty(2)