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Re: select()
- To: "Todd M. Grimm" <grimm at itd dot nrl dot navy dot mil>
- Subject: Re: select()
- From: Harry Broomhall <haeb at demon dot net>
- Date: Fri, 9 Oct 1998 11:47:42 +0100 (BST)
- Cc: gnu-win32 at cygnus dot com
Todd M. Grimm said:
>
> I am using select() to test whether there are bytes on a socket to read
> without blocking my program to check on this.
>
> The problem is that even when there is no data it returns a 1 to say that
> there is data. This causes my program to try a read which blocks because
> there really is no data.
>
> I saw several messages in the archives of this list about this, but all I
> could find were questions. No one ever seemed to answer the question.
>
> Please let me know if you know how to get select() to work right or if
> there is a nother way to test for bytes without blocking.
Without seeing the code it is impossible to judge what is
happening, but in general, select returns whether a socket is
*ready*, not just readable. For example, if the other end has
closed the connection select() will return that the socket is
ready. A read on the socket will return 0 to indicate the
close.
Regards,
Harry.
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