Php/docs/intro.eio
This extension provides asyncronous POSIX I/O by means of » libeio C library written by Marc Lehmann.
Note:
This extension is notavailable on Windows platforms.
Warning It is important to be aware that each request is executed in a thread, and the order of execution of continuously queued requests basically is unpredictable. For instance, the following piece of code is incorrect.
Example #1 Incorrect requests
<?php// Request to create symlink of $filename to $linkeio_symlink($filename, $link);// Request to move $filename to $new_filenameeio_rename($filename, $new_filename);// Process requestseio_event_loop();?>
In the example above eio_rename() request may finish before eio_symlink(). To fix it you might call eio_rename() in the callback of eio_symlink():
Example #2 Calling request from a request callback
<?phpfunction my_symlink_done($filename, $result) { // Request to move $filename to $new_filename eio_rename($filename, "/path/to/new-name"); // Process requests eio_event_loop();}// Request to create symlink of $filename to $linkeio_symlink($filename, $link, EIO_PRI_DEFAULT, "my_symlink_done", $filename);// Process requestseio_event_loop();?>
Alternatively, you might want to create a request group:
Example #3 Calling request from a request callback
<?php/* Is called when the group requests are done */function my_grp_done($data, $result) { // ...}function my_symlink_done($filename, $result) { // Create eio_rename request and add it to the group $req = eio_rename($filename, "/path/to/new-name"); eio_grp_add($grp, $req); // You might want to add more requests...}// Create a request group$grp = eio_grp("my_grp_done", "my_grp_data");// Create eio_symlink request and add it to the group// Pass $filename to the callback$req = eio_symlink($filename, $link, EIO_PRI_DEFAULT, "my_symlink_done", $filename);eio_grp_add($grp, $req);// Process requestseio_event_loop();?>
Group is a special kind of request that could accumulate a set of regular eio requests. This could be used to create a complex request that opens, reads and closes a file. Since version 0.3.0 alpha, a variable used in communications with libeio internally, could be retrieved with eio_get_event_stream(). The variable could be used to bind to an event loop supported by some other extension. You might organize a simple event loop where eio and libevent work together:
Example #4 Using eio with libevent
<?phpfunction my_eio_poll($fd, $events, $arg) { /* Some libevent regulation might go here .. */ if (eio_nreqs()) { eio_poll(); } /* .. and here */}function my_res_cb($d, $r) { var_dump($r); var_dump($d);}$base = event_base_new();$event = event_new();// This stream is used to bind with libevent$fd = eio_get_event_stream();eio_nop(EIO_PRI_DEFAULT, "my_res_cb", "nop data");eio_mkdir("/tmp/abc-eio-temp", 0750, EIO_PRI_DEFAULT, "my_res_cb", "mkdir data");/* some other eio_* calls here ... */// set event flagsevent_set($event, $fd, EV_READ /*| EV_PERSIST*/, "my_eio_poll", array($event, $base));// set event base event_base_set($event, $base);// enable eventevent_add($event);// start event loopevent_base_loop($base);/* The same will be available via buffered libevent interface */?>
