readline_callback_handler_install
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
readline_callback_handler_install — Initializes the readline callback interface and terminal, prints the prompt and returns immediately
Description
Sets up a readline callback interface then prints
prompt and immediately returns.
Calling this function twice without removing the previous
callback interface will automatically and conveniently overwrite the old
interface.
The callback feature is useful when combined with stream_select() as it allows interleaving of IO and user input, unlike readline().
Parameters
-
prompt -
The prompt message.
-
callback -
The
callbackfunction takes one parameter; the user input returned.
Return Values
Returns true on success or false on failure.
Examples
Example #1 Readline Callback Interface Example
<?php
function rl_callback($ret)
{
global $c, $prompting;
echo "You entered: $ret\n";
$c++;
if ($c > 10) {
$prompting = false;
readline_callback_handler_remove();
} else {
readline_callback_handler_install("[$c] Enter something: ", 'rl_callback');
}
}
$c = 1;
$prompting = true;
readline_callback_handler_install("[$c] Enter something: ", 'rl_callback');
while ($prompting) {
$w = NULL;
$e = NULL;
$n = stream_select($r = array(STDIN), $w, $e, null);
if ($n && in_array(STDIN, $r)) {
// read a character, will call the callback when a newline is entered
readline_callback_read_char();
}
}
echo "Prompting disabled. All done.\n";
?>
See Also
- readline_callback_handler_remove() - Removes a previously installed callback handler and restores terminal settings
- readline_callback_read_char() - Reads a character and informs the readline callback interface when a line is received
- stream_select() - Runs the equivalent of the select() system call on the given arrays of streams with a timeout specified by seconds and microseconds
