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From: fkittred@bbn.com (Fletcher Kittredge)
Newsgroups: comp.unix.ultrix
Subject: Re: select() on named pipes
Message-ID: <55729@bbn.BBN.COM>
Date: 4 May 90 11:37:11 GMT
References: <9731@wiley.UUCP>
Sender: news@bbn.com
Reply-To: fkittred@spca.bbn.com (Fletcher Kittredge)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 36

In article <9731@wiley.UUCP> rudoff@mdi.com writes:
...Problems with select on a 3100...
>main()
>{
...
>        n = select(1, &readfds, NULL, NULL, &timeout);
...
>}
>
..it doesn't work for him...

Your problem is your first argument to select; you have hardcoded
it to '1' when it should be variable. It should always be one greater
than the largest file descriptor you are interested in.  In this case,
it should be (readfds + 1).

>I have select() working elsewhere with stdin so I think I'm using it
>correctly. Am I doing something wrong here or is there a problem with
>select() and pipes in Ultrix 3.1?

It works on stdin because with stdin your readfds is 0, so (readfds + 1)
is 1....

>
>Doug Rudoff
>Mobile Data International
>(206) 487-5937
>uunet!mdisea!rudoff, rudoff@MDI.COM



Fletcher E. Kittredge  fkittred@bbn.com
Platforms and Tools Group
BBN Software Products Company
10 Fawcett St.
Cambridge, MA. 02138