Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!wrdis01!gatech!bloom-beacon!eru!hagbard!sunic!mcsun!hp4nl!integow!theo
From: theo@integow.uucp (Theo Hardendood)
Newsgroups: comp.unix.programmer
Subject: Re: Understanding select...
Message-ID: <1580@integow.uucp>
Date: 18 Apr 91 08:40:56 GMT
References: <533@shrike.AUSTIN.LOCKHEED.COM>
Organization: Integrity BV, Woerden, the Netherlands
Lines: 35

From article <533@shrike.AUSTIN.LOCKHEED.COM>, by dcj@AUSTIN.LOCKHEED.COM (David Jacobson rimux):
>   I would like to use the select command to sit on a serial device
> object descriptor (fd) and come off the select when any data has come
> in.
> 
> Q1:  Is this possible?
> 

Yes (although I read somewhere that not all devices support select calls)

> descriptor.  Unfortunately, my program sits on my select and never comes
> off.
> 
> Q2:  Do you see the error in my concept of select or in my code below?
> 

... (some stuff deleted)

> 
>    FD_ZERO(&readmask);
>    FD_SET(fd, &readmask);
>    maxfdp1 = fd++;
               ^^^^

This must be:

     maxfdp1 = fd + 1;

Hope this helps!

-- 
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Theo Hardendood, Sr. software engineer, Integrity software consultants, 
         Pelmolenlaan 2, 3447 GW  Woerden, The Netherlands.
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