(PHP 5 >= 5.1.0, PHP 7)
readline_callback_read_char — Reads a character and informs the readline callback interface when a line is received
Reads a character of user input. When a line is received, this function informs the readline callback interface installed using readline_callback_handler_install() that a line is ready for input.
No value is returned.
See readline_callback_handler_install() for an example of how to use the readline callback interface.