Subj : Re: Threading and Timeouts
To   : comp.programming.threads
From : Giancarlo Niccolai
Date : Tue Jul 26 2005 10:41 am

Charles Bryant wrote:

> In article <42de49df$0$70709$e4fe514c@news.xs4all.nl>,
> Casper H.S. Dik  <Casper.Dik@Sun.COM> wrote:
>>Giancarlo Niccolai <searchforme@ingoogle.com> writes:
>>
>>
>>>Select works with WinSocks too, although with a couple of minor,
>>>irrelevant differences (i.e. the first parameter, that is, maxfd + 1, is
>>>ignored).
>>
>>That's not really a irrelevant difference; the caller of select is
>>free to put garbage in the sets past the index of maxfd.
> 
> There's another very relevant difference. From:
> 
> <URL: http://msdn.microsoft.com/library/
> en-us/winsock/winsock/select_2.asp >
> 
> ! Any two of the parameters, readfds, writefds, or exceptfds, can be given
> ! as null. At least one must be non-null, and any non-null descriptor set
> ! must contain at least one handle to a socket.
> 
> This is very non-intuitive and a considerable nuisance. It means that if
> you have a program where you need to accommodate a varying number of
> sockets being used with select(), you need to have special handling for
> the cases where there happen to be no sockets currently in each of the
> sets. It also means that the common idiom to get a microsecond-resolution
> pause:
> select(0, 0, 0, 0, x)
> breaks on Windows.

Yes, indeed this is really a nuisance.

GN.

.