. PHP Manual . Prev . Next . (PHP 4 >= 4.0.0) readline_completion_function -- Registers a completion function . bool readline_completion_function ( string line) . This function registers a completion function. You must supply the name of an existing function which accepts a partial command line and returns an array of possible matches. This is the same kind of functionality you'd get if you hit your tab key while using Bash. Prev . Home . Next . readline_clear_history . Up . readline_info