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From: alweiner@clark.net (Alan Weiner)
Newsgroups: comp.unix.bsd.bsdi.misc
Subject: Re: Major bug? (probably programmer error :)
Date: 4 Sep 1995 20:58:53 GMT
Organization: GRYPHON Microproducts
Lines: 20
Message-ID: <42fpad$rie@clarknet.clark.net>
References: <42ff8m$b3d@clarknet.clark.net> <VIXIE.95Sep4112251@wisdom.vix.com>
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In article <VIXIE.95Sep4112251@wisdom.vix.com>, vixie@wisdom.vix.com (Paul A Vixie) says:
>
>> lseek(fd,-1L*sizeof(b),1);
>> write(fd,&b,sizeof(b));
>>
>> Try running the following program on your BSDI system. I think you'll be
>> supprized at the resulting test.txt.
>
>Nope, no surprises here.
>
>> Am I doing something illegal here?
>
>Try this:
>
> printf("offset: %ld\n", -1L*sizeof(b));
>
>What you've done is to create a sparse file. Only the blocks you've written
>on will be allocated. Try "ls -ls test.txt" and you'll see what I mean.
Doesn't -1L*sizeof(b) do an implicit conversion to long?