Homo-Adminus Blog - Latest Comments in Using epoll() For Asynchronous Network Programming

Re: Using epoll() For Asynchronous Network Programming

addisu — Tue, 26 Aug 2008 21:22:57 -0000

Great write up. I couldn't find a more detailed example than this. However, how do you know when a client closes a connection? It seems that you should be able to check your event against EPOLLHUP but the event number shown when a client closes is 0x5 while EPOLLHUP is defined as 0x10. So is there some bit masking I have to do?

Thanks,
Addisu

Re: Using epoll() For Asynchronous Network Programming

Sergey Maranchuk — Thu, 31 Jul 2008 09:35:02 -0000

занимательно, надо будет py-epoll погонять)
тем более сейчас джангу перевёл на асинхронный сервер который использует epoll В)

кстати если не ошибаюсь, результатом C10K problem стал сервер lighttpd

Re: Using epoll() For Asynchronous Network Programming

James — Sun, 20 Jul 2008 12:31:23 -0000

actually "fd" is not "used" for epolling. The fd is passed separately to epoll_wait, the data structure is used for passing in any data the user requires. As it is a union structure writing to "void *ptr" will overwrite fd.

This data structure is useful for passing in data that may be useful to the user of the data. For example you can cache data that has been gathered by the connection previously and then store this in a structure which the void *ptr points to. When more data is ready you then have access to the previously stored data which you can add to with the further communication.

James

Re: Using epoll() For Asynchronous Network Programming

Prashanth — Mon, 07 Jul 2008 02:32:55 -0000

Hi,

Thanks for the info for epoll. These are helpful.

I had one question regarding the user data variable given as part of epoll_event structure.
If only "fd" is used for epolling, why are u32/u64 and void pointers provided.

thanks,
Prashanth

Re: Using epoll() For Asynchronous Network Programming

Mr Mister — Tue, 23 Oct 2007 15:08:41 -0000

Sonny,
Just use google's translator. CLick this link to see a translation (should help a little):
http://translate.google.com...

Re: Using epoll() For Asynchronous Network Programming

Sonny — Tue, 04 Sep 2007 04:29:57 -0000

I found a website with an epoll example written by zhoulifa(zhoulifa@163.com). Its comments are in chinese, could anyone translate it/document it in english so it will be understood better? http://zhoulifa.bokee.com/6...

Btw, why must it avoid nonblocking on function handle_io_on_socket? It accessing db like MySQL nonblocking?

Re: Using epoll() For Asynchronous Network Programming

MunkeN — Sun, 26 Aug 2007 09:42:52 -0000

Eranga, yes.

OT: Great tutorial, even though you never declared events.
Well done Scoundrel.

Re: Using epoll() For Asynchronous Network Programming

Eranga — Thu, 28 Jun 2007 09:15:44 -0000

Is it possible to use FD (file descriptor) meant for poll() with epoll()?

Re: Using epoll() For Asynchronous Network Programming

Nathan Mickulicz — Sat, 23 Jun 2007 16:26:53 -0000

Not if you use the aio functions.

Re: Using epoll() For Asynchronous Network Programming

connection — Fri, 27 Oct 2006 12:46:39 -0000

This is exactly what I was looking for, thanks for the great information.

Re: Using epoll() For Asynchronous Network Programming

JoelKatz — Fri, 14 Apr 2006 14:15:47 -0000

It should be pointed out that if you use this approach, all code from handle_io_on_socket must avoid blocking no matter what. This can be nearly impossible in an application that's not multi-threaded.