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From: matt@oddjob.UUCP (Matt Crawford)
Newsgroups: net.bugs.4bsd
Subject: Re: interrupted select() buggy if no timeout is specified (4.2BSD)
Message-ID: <729@oddjob.UUCP>
Date: Thu, 16-May-85 18:57:23 EDT
Article-I.D.: oddjob.729
Posted: Thu May 16 18:57:23 1985
Date-Received: Fri, 17-May-85 05:13:13 EDT
References: <163@Gregorio.ARPA>
Reply-To: matt@oddjob.UUCP (Matt Crawford)
Distribution: net
Organization: U. Chicago, Astronomy & Astrophysics
Lines: 17

In article <163@Gregorio.ARPA> mogul@Gregorio.ARPA writes:
>
>Description:
>	If select() is called with a null pointer for the "timeout"
>	argument, and then interrupted, it fails to modify the
>	bit mask arguments, thus implying that all descriptors
>	are ready (although they may not be).
>	....

If you do not test the return value of select() your program is wrong.
Only use the mask values if the return value is strictly greater than 0.
The manual page says that it is a bug that the masks are ever modified
when select times out.  The same comment should also be made about
interrupts.  In fact, the pyramid does not have this bug.  
_____________________________________________________
Matt		University	crawford@anl-mcs.arpa
Crawford	of Chicago	ihnp4!oddjob!matt