Why does file_get_contents take twice the time of default_socket_tieout when timeout occurs?

Hello, I use file_get_contents to access to a web api. It's timeout is set by default_socket_timeout. When a web api took a long time to response, of course file_get_contents timed out. But It seemed strange. file_get_contents took more time than default_socket_timeout. For reproducing this problem, I prepared the program that took enough time to cause timeout and I tested file_get_contents. As a result, I found that file_get_contents takes twice the time of default_socket_tieout when timeout occurs. For example, when I set default_socket_timeout to 3 sec, file_get_contents takes 6 seconds to return the result. Why does file_get_contents take twice the time of default_socket_tieout when timeout occurs? ###### # code # ###### -------------------------------------------------- <?php ini_set('default_socket_timeout', 3); echo file_get_contents('http://foo.bar.jp/sleep'); -------------------------------------------------- # If I use curl module, this problem doesn't occur. -------------------------------------------------- <?php $ch = curl_init('http://foo.bar.jp/sleep'); curl_setopt($ch, CURLOPT_TIMEOUT, 3); curl_exec($ch); curl_close($ch); -------------------------------------------------- ########## # php version # ########## $ php --version PHP 5.4.6 (cli) (built: Jun 19 2014 17:43:25) Copyright (c) 1997-2012 The PHP Group Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies ------ Masahiro Honma