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From: chris@nrcvax.UUCP (Chris Grevstad)
Newsgroups: comp.unix.wizards
Subject: Re: unlinking open files (was Re: Seek on a pipe)
Message-ID: <960@nrcvax.UUCP>
Date: Sun, 21-Jun-87 15:42:03 EDT
Article-I.D.: nrcvax.960
Posted: Sun Jun 21 15:42:03 1987
Date-Received: Tue, 23-Jun-87 04:26:13 EDT
References: <6695@auspyr.UUCP>
Reply-To: chris@minnie.UUCP (Chris Grevstad)
Organization: Frobozo Items Co. Inc. Ltd.
Lines: 31

mick@auspyr.UUCP (Mick Andrew) says:
>in article <7074@mimsy.UUCP>, chris@mimsy.UUCP (Chris Torek) says:
>>  * We use the despicable trick of unlinking an open temporary file.
>>  * The alternatives are too painful.  
> ...
> ...
>But for real-world honest-to-god live applications, this seems like the
>best solution to avoid leaving temp file clutter lying around
>on poorly understood and administered Unix boxes.
>

Well, there are a couple of problems with this approach in real life.  First
is that it is not necessarily portable.  VMS refuses to unlink an open file.
I would make the assumption that there are other os's that feel the same way.

Another problem is when you later need to reference this unlinked file by its
name, rather than file handle (either fd or fp).  Tough to do when the file's
already gone.

VMS attempts to solve this problem by having an additional flag on open, to
indicate that this is indeed a temporary file and should be deleted on the
last close.  Unfortunately, it's functionally equivalent to, under UNIX,
unlinking an open file, thus removing the file name from the file system and
making it invisible for other applications that might need to see the file.

-- 
	Chris Grevstad
	{sdcsvax,hplabs}!sdcrdcf!psivax!nrcvax!chris
	ihnp4!nrcvax!chris

As Mad Max was wont to say: So-so-so-so-so-so-sorry about that, Chief!