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From: imp@bsdimp.com (Warner Losh)
Subject: [TUHS] History of strncpy
Date: Thu, 24 Jan 2013 07:52:34 -0700	[thread overview]
Message-ID: <EC8F3C9A-F979-4B6E-911A-12947F061FD2@bsdimp.com> (raw)
In-Reply-To: <1AFADE66-7F72-4776-8738-EC27748DAF33@ronnatalie.com>


On Jan 24, 2013, at 7:42 AM, Ronald Natalie wrote:

> 
> On Jan 24, 2013, at 1:02 AM, Larry McVo
>> As a SPARC guy (in the past), I think it may have had something to do 
>> about alignment.
>> 
>> That said, I hate the fread/fwrite interfaces.  We're fixing them in 
>> our stdio.  freadn(f, buf, n).
>> 
> Amen.    For practical matters, there is no way given the rest of the library that an implementation can do
> anything other than multiply the two middle args together.    The stream still needs to be a byte stream
> and passing things as void* sort of divorces any clue as to what alignment or other portability requirements
> are (and I've worked on C on some rather odd word sized machines like 36 and 60 as well as machines
> that encode the word size in the pointer... believe me there were TONS of bugs in 4BSD with regard to that
> one where they would stuff a char* into a union and retrieve it with a int* thwarting any possible conversion
> (as we put in place when you casted one pointer to other).

Historically the only implementation I know that didn't just multiply the two args together was on VAX/VMS's VAXC. The underlying filesystem had a notion of a file of records, so you'd get very different result from n * size, 1 and n, size. The former would produce one record that was n * size, while the latter would produce n records, each of which was size in length. As with all things on that compiler, this was only sometimes, and it greatly depended on how the file was created... Mostly a royal pain, except in some very rare instances where it was what you wanted to happen.

Warner

> It's not true that FILE went at the end, except in vararg'd functions.   It goes at the beginning of ftell (which
> mimics the UNIX  tell call).    As with Larry, I'd much perferred they mimic'd most of the UNIX calls when
> possible.   They were reasonably thought out.
> 
> _______________________________________________
> TUHS mailing list
> TUHS at minnie.tuhs.org
> https://minnie.tuhs.org/mailman/listinfo/tuhs




  reply	other threads:[~2013-01-24 14:52 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-23 17:56 Michael Spacefalcon
2013-01-23 21:08 ` Larry McVoy
2013-01-23 21:39 ` Ronald Natalie
2013-01-23 21:46   ` John Cowan
2013-01-24  6:02     ` Larry McVoy
2013-01-24  6:34       ` Steve Nickolas
2013-01-24 14:42       ` Ronald Natalie
2013-01-24 14:52         ` Warner Losh [this message]
2013-01-24 16:01           ` Ronald Natalie
2013-01-24 18:31             ` Tom Ivar Helbekkmo
2013-01-25  2:06               ` Warner Losh
2013-01-24 16:21           ` Clem Cole
2013-02-01  0:28             ` Larry McVoy
2013-01-31 23:52           ` Random832
2013-02-01  0:06             ` Warner Losh
  -- strict thread matches above, loose matches on Subject: below --
2013-01-23  4:03 Nevin Liber
2013-01-23  4:41 ` Warren Toomey
2013-01-23  4:58 ` Warner Losh
2013-01-23 14:16 ` Clem Cole
2013-01-23 15:01   ` Ronald Natalie
2013-01-23 15:24     ` Armando Stettner
2013-01-23 17:49       ` scj
2013-01-23 18:19       ` Ronald Natalie
2013-01-23 19:33         ` Ronald Natalie
2013-01-23 19:59           ` Clem Cole
2013-01-23 22:43     ` Mary Ann Horton
2013-01-24  0:01       ` Clem Cole
2013-01-24  0:37 ` Jonathan Gevaryahu

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