Re: select() fails... sometimes

Alex Belits (abelits@phobos.illtel.denver.co.us)
Wed, 19 May 1999 16:28:37 -0700 (PDT)


On Tue, 18 May 1999 mgarcia@bjssoft.es wrote:

> I have a problem using select() on several handles.
> It does work fine but, under some circumstances, it returns inmediately ignoring the timeout argument, indicating that handle zero (stdin linked to a socket via inetd) has something to read, but "read()" gets nothing at all.
>
> Once it happens it doesn't stop until something is received by some other handle. It's very annoying since the CPU load grows enormeously.
>
> It always happens with stdin (zero). I've tried the following settings for stdin without success:
>
> fcntl( 0, F_SETFL, O_NONBLOCK );
> setvbuf( stdin, NULL, _IONBF, 0 );
>
> Any ideas?

If select() set a bit in readfds, and read() on that fd returned zero,
it means that whatever is attached to that fd is finished, this fd
must be closed, and no further i/o should be attempted on it. In your case
stdin is a socket, and other end closed it or disconnected for whatever
other reason.

-- 
Alex

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