WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

Jan Koen Annot — Fri, 05 Oct 2012 12:41:27 GMT

For Microsoft, it is a known issue:

"Windows 8 Bugs 309411 - WSAPoll does not report failed connections

8/3/2011 6:53 PM Resolved as Won't Fix by muraris

Has been like this forever and people are already used to it."

"The recommendation for now is to not use the WSAPoll function it in case you encounter this issue, but rather the other Net-API functions."

See curl.haxx.se/.../0038.html for further discussion.

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

Aris Adamantiadis — Tue, 03 May 2011 13:21:20 GMT

Hello,

Could you advise on this ?

social.msdn.microsoft.com/.../18769abd-fca0-4d3c-9884-1a38ce27ae90

We're bitten by this problem on our project, which makes WSAPoll completely useless. Are there known workarounds ? I'm thinking os putting an arbitrary timeout or going back to good old select (which doesn't look so buggy).

Thanks,

Aris

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

Jeff Koftinoff — Wed, 19 Aug 2009 21:36:27 GMT

I'm coming in late to this discussion, but the quiet often the best thing to do if you are using c++ is to use the boost::asio networking library. You program it in the style of IO Completion, and the program would work on all platforms regardless if it is internally using select, poll, epoll, or IO completion ports.

--jeffk++

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

Paul Sheer — Sun, 30 Nov 2008 04:36:52 GMT

WSAPoll() vs select() performance -

I would like to know the performance of WSAPoll() compared to select() on Windows. You see, porting between select() and WSAPoll() is not a major effort. With both functions you inquire before you act.

Porting to IO completion is a MAJOR change in program design for my application. Here you do the IO action FIRST and then wait for notification that it has happened.

If you say that WSAPoll() gives substantialy better peformance than select(), then I'll try it. If I know in advance then it will save me a lot of time. That WSAPoll does not work on Windows XP is a huge problem BTW. It means you can't create a portable EXE.

Any way around this? Is Microsoft going to issue a service pack so XP guys can use this?

This is one of thoose, write a little bit of code to see for yourself if it will help. Generally speaking, the best model is posting recv/sends with completion ports, so if you are going to change models, look at that first. I believe this api is there to help with porting of applications already on the poll model.

To deal with backwards compatability, I generally attempt to dynamically load any function ptrs that might not be present at startup and then choose my implementation based on the api sets available. Good Luck. -- Ari

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

JGresham — Mon, 13 Oct 2008 19:38:47 GMT

Any articles to point us to settings/config to get apps using the legacy winsock api to work in vista.

Getting network errors unable to connect to host in vista. Xp and older works fine. But have not found a fix for this and a reset of the catalog does not help.

Thanks

Could this have to do with IPV6 being on by default in Vista? What's do you see in a netmon sniff?

-- Ari

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

Avinash — Wed, 30 Jul 2008 01:40:37 GMT

Can you please comment on the performance of WSAPoll vs select on win and WSAPoll vs poll on linux.

I am seeing a perf issue where using select degrades performace by 40%. On linux the performace is almost the same with or without using the poll.

Thx

Select on Windows is mostly for compatibility not performance. If you are focused on performance and scalability there are better IO models to use.

-- Ari

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

3h — Fri, 04 Apr 2008 04:04:53 GMT

It is not working on Windows XP + Visual Studio 5.0 as I tested.

WSAPoll is Vista and higher (Server 2008)
-- Ari

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

wndpteam — Tue, 14 Nov 2006 23:11:26 GMT

Thank you for your thoughtful comments.

I just double checked that the SOCKADDR_STORAGE structure is isomorphic with the sockaddr structure. It's two benefits are that it is large enough to store v4 or v6 addresses and due to its padding will maintain 64-bit alignment. RFC 2553 at ietf.org has additional recommendations regarding its use.

As a practical matter, I agree that you should put the socket in to non-blocking mode in case, for example, the size of the send exceeds available buffer space. In the sample shown above, WSAPoll guarantees that the call to send will not block.

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

comment — Tue, 14 Nov 2006 21:33:49 GMT

You forgot to mention that the socket must be in non-blocking mode before doing the I/O operation.

re: WSAPoll, A new Winsock API to simplify porting poll() applications to Winsock.

EvanR — Sun, 12 Nov 2006 01:47:32 GMT

Actually on BSD and Linux you would use struct addrinfo, which is the preferred method to write ip-agnostic apps. Use that instead of SOCKADDR_STORAGE if you can, then it will work on both platforms.