Bug #63411 [Fbk]: curl_multi_select() returns invalid value

Edit report at https://bugs.php.net/bug.php?id=63411&edit=1 ID: 63411 Updated by: pierrick@php.net Reported by: marcel at silverstreet dot com Summary: curl_multi_select() returns invalid value Status: Feedback Type: Bug Package: cURL related Operating System: CentOS 6.3 PHP Version: 5.3.18 Assigned To: pierrick Block user comment: N Private report: N New Comment: As mentioned in bug #61141, curl_multi_select() returning -1 is an expected behaviour and you should not throw an exception which prevent your call to be done. Internally php curl_multi_select uses libcurl curl_multi_fdset function to set all the fd_set and the maxfd value. The libcurl curl_multi_fdset documentation says : When libcurl returns -1 in max_fd, it is because libcurl currently does something that isn't possible for your application to monitor with a socket and unfortunately you can then not know exactly when the current action is completed using select(). When max_fd returns with -1, you need to wait a while and then proceed and call curl_multi_perform anyway. How long to wait? I would suggest 100 milliseconds at least, but you may want to test it out in our own particular conditions to find a suitable value. The workaround you made is not really a workaround, but is exactly what libcurl recommend you to do in this case :) Previous Comments: ------------------------------------------------------------------------ [2012-11-15 11:42:21] bfanger at gmail dot com curl_multi_select() returning -1 has been an issue for windows versions of PHP for a while: https://bugs.php.net/bug.php?id=61141 A workaround for my Curl wrapper class was to rewrite: if (curl_multi_select(self::$pool, 0.2) === -1) { throw new \Exception('Failed to detect changes in the cURL multi handle'); } To: if (curl_multi_select(self::$pool, 0.2) === -1) { usleep(100000); // wait 0.1 second } PS: When are you going to introduce the new curl_multi_wait function to php? ------------------------------------------------------------------------ [2012-11-15 09:30:31] bfanger at gmail dot com It breaks all my testcases in PHP 5.4.8 (works fine in 5.4.7) $ git clone git://github.com/sledgehammer/core.git testapp/core $ phpunit --bootstrap testapp/core/phpunit_bootstrap.php testapp/core/tests/CurlTest.php ------------------------------------------------------------------------ [2012-11-15 05:39:33] pierrick@php.net Does it break all the test cases ? Or only like in your case when you have no handle ? ------------------------------------------------------------------------ [2012-11-05 15:21:29] aa dot vasilenko at gmail dot com This bug breaks existing libs, like Buzz https://github.com/kriswallsmith/Buzz , that relies on curl_multi_* functions. This is how I came here. ------------------------------------------------------------------------ [2012-11-03 03:42:09] pierrick@php.net I'm not sure we really want to wait 1 second for nothing in this specific case. Furthermore, as mentioned in my commit message, when libcurl returns -1 in max_fd after calling curl_multi_fdset, it is because libcurl currently does something that isn't possible for your application to monitor with a socket and unfortunately you can then not know exactly when the current action is completed using select(). I would personally keep the current behaviour. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=63411 -- Edit this bug report at https://bugs.php.net/bug.php?id=63411&edit=1