php man page for readline_callback_handler_install

READLINE_CALLBACK_HANDLER_INSTALL(3)					 1				      READLINE_CALLBACK_HANDLER_INSTALL(3)

readline_callback_handler_install - Initializes the readline callback interface and terminal, prints the prompt and returns immediately

SYNOPSIS
       bool readline_callback_handler_install (string  $prompt, callable  $callback)

DESCRIPTION
	Sets up a readline callback interface then prints $prompt and immediately returns. Calling this function twice without removing the previ-
       ous callback interface will automatically and conveniently overwrite the old interface.

	The callback feature is useful when combined with stream_select(3) as it allows interleaving of IO and user input, unlike readline(3).

PARAMETERS
	      o $prompt
		- The prompt message.

	      o $callback
		- The $callback function takes one parameter; the user input returned.

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

       Example #1

	      Readline Callback Interface Example

	      <?php
	      function rl_callback($ret)
	      {
		  global $c, $prompting;

		  echo "You entered: $ret
";
		  $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.
";
	      ?>

       readline_callback_handler_remove(3), readline_callback_read_char(3), stream_select(3).

PHP Documentation Group 										      READLINE_CALLBACK_HANDLER_INSTALL(3)