TCSAFLUSH
TCSAFLUSH is a constant defined in termios.h and used as the optional_actions parameter to the POSIX tcsetattr function. It indicates that the change to the terminal attributes should occur after flushing both the input and the output queues. The name derives from the idea of flushing (discarding) pending data before applying the new settings.
When tcsetattr is called with TCSAFLUSH, any data still in the input queue and any data waiting
Typical usage involves including termios.h and calling tcsetattr with the desired file descriptor of a terminal
Compatibility: TCSAFLUSH is defined by POSIX. It is supported on most UNIX-like systems, including Linux and