FIONREAD2const
Buffer count and flushing
Usage
#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);
Library
Standard C library (libc, -lc)
Overview
- 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_TEMTbit 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_TEMTbit is set.
Return value
On success, 0 is returned. On error, -1 is returned, and errno is set to indicate the error.
Releases
2 releases since Debian 13 (Trixie); the text changed 1 time.