Re: sprintf and the trailing null

From	Phil Carmody <pc+usenet@asdf.org>
Newsgroups	comp.lang.c
Subject	Re: sprintf and the trailing null
Date	2015-07-10 17:06 +0300
Organization	A noiseless patient Spider
Message-ID	<87si8wayyl.fsf@bazspaz.fatphil.org> (permalink)
References	(7 earlier) <87zj36d19c.fsf@bazspaz.fatphil.org> <e83cec81-7c17-4630-94ff-2f47bdbc971b@googlegroups.com> <mnjofu$2fs$1@dont-email.me> <8c2e28ac-e95b-4b1b-a870-08eb4a97c122@googlegroups.com> <mnm65o$aal$1@dont-email.me>

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Richard Heathfield <rjh@cpax.org.uk> writes:
> On 09/07/15 17:02, David Kleinecke wrote:
> > On Wednesday, July 8, 2015 at 11:02:05 AM UTC-7, Bart wrote:
> 
> <omitting the null terminating character from *printf output>
> 
> >> I think the idea to use %!, or any other accompanying code, is better.
> >
> > Not that I much care about the % but I wonder what the best way
> > would really be.
> 
> The best way would be not to do it at all.
> 
> The *printf functions are generally used either for writing to a text
> stream (in which case the null character isn't written anyway) or to a
> string (in which case the null character is required, because
> otherwise it isn't a string).

Many of the str* functions do not require actual strings as their
parameters, merely (pointers to (first elements of)) arrays.
strncpy is the most obvious example, but I know that's a bit of
an embarassment to some as an outsider. Look for "array" in the
descriptions of the str* funcs.

But also look at the punchy 1-sentence summary of the behaviour
of sprintf before holding too firm to your assersions:
"""
The sprintf function is equivalent to fprintf, except that the output
is written into an array (speci#ed by the argument s) rather than to a
stream.
"""
fprintf outputs data, not strings. The destination is merely an array
not a "string" (as per the destination of strncpy). Mention of null
termination is secondary (the following sentence). One could implement
the trailing-% tweak without changing that initial sentence. OK, you'd
have to tweak the second one. but I believe in the inverted pyramid.

Phil
-- 
A well regulated militia, being necessary to the security of a free state,
the right of the people to keep and bear arms, shall be well regulated.

Thread

sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 06:16 -0700
  Re: sprintf and the trailing null John McCue <jmccue@jmcnet1.bstnma.east.verizon.net> - 2015-07-06 13:30 +0000
    Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 06:37 -0700
      Re: sprintf and the trailing null Reinhardt Behm <rbehm@hushmail.com> - 2015-07-06 21:58 +0800
        Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 07:12 -0700
          Re: sprintf and the trailing null Reinhardt Behm <rbehm@hushmail.com> - 2015-07-06 22:34 +0800
            Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 08:44 -0700
          Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-06 15:46 +0100
            Re: sprintf and the trailing null Keith Thompson <kst-u@mib.org> - 2015-07-06 08:06 -0700
              Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-06 17:42 +0100
                Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 09:48 -0700
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-06 18:07 +0100
                Re: sprintf and the trailing null Martin Shobe <martin.shobe@yahoo.com> - 2015-07-06 12:40 -0500
                Re: sprintf and the trailing null Keith Thompson <kst-u@mib.org> - 2015-07-06 10:46 -0700
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-06 18:58 +0100
          Re: sprintf and the trailing null Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-06 16:38 +0100
            Re: sprintf and the trailing null Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-06 23:44 +0100
              Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 15:48 -0700
              Re: sprintf and the trailing null Phil Carmody <pc+usenet@asdf.org> - 2015-07-08 20:09 +0300
                Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-08 10:11 -0700
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-08 19:01 +0100
                Re: sprintf and the trailing null David Kleinecke <dkleinecke@gmail.com> - 2015-07-09 09:02 -0700
                Re: sprintf and the trailing null Richard Heathfield <rjh@cpax.org.uk> - 2015-07-09 17:07 +0100
                Re: sprintf and the trailing null Phil Carmody <pc+usenet@asdf.org> - 2015-07-10 17:06 +0300
                Re: sprintf and the trailing null glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-09 17:42 +0000
                Re: sprintf and the trailing null Phil Carmody <pc+usenet@asdf.org> - 2015-07-10 13:33 +0300
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-10 12:09 +0100
                Re: sprintf and the trailing null Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-10 04:51 -0700
                Re: sprintf and the trailing null Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-10 17:24 +0100
                Re: sprintf and the trailing null Keith Thompson <kst-u@mib.org> - 2015-07-10 08:33 -0700
                Re: sprintf and the trailing null Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-11 04:58 -0700
      Re: sprintf and the trailing null jt@toerring.de (Jens Thoms Toerring) - 2015-07-06 14:15 +0000
        Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 07:20 -0700
          Re: sprintf and the trailing null raltbos@xs4all.nl (Richard Bos) - 2015-07-06 19:54 +0000
            Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 13:31 -0700
              Re: sprintf and the trailing null Richard Heathfield <rjh@cpax.org.uk> - 2015-07-06 21:52 +0100
              Re: sprintf and the trailing null raltbos@xs4all.nl (Richard Bos) - 2015-07-06 22:52 +0000
                Re: sprintf and the trailing null Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-07 01:04 +0100
                Re: sprintf and the trailing null Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-06 19:13 -0700
                Re: sprintf and the trailing null Reinhardt Behm <rbehm@hushmail.com> - 2015-07-07 12:45 +0800
                Re: sprintf and the trailing null Rosario19 <Ros@invalid.invalid> - 2015-07-07 10:15 +0200
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-07 10:31 +0100
                Re: sprintf and the trailing null Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-07 02:51 -0700
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-07 12:10 +0100
                Re: sprintf and the trailing null Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-07 05:08 -0700
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-07 13:52 +0100
                Re: sprintf and the trailing null Phil Carmody <pc+usenet@asdf.org> - 2015-07-08 20:20 +0300
                Re: sprintf and the trailing null Bartc <bc@freeuk.com> - 2015-07-08 18:51 +0100
                Re: sprintf and the trailing null raltbos@xs4all.nl (Richard Bos) - 2015-07-09 10:27 +0000
                Re: sprintf and the trailing null Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-10 19:03 -0700
              Re: sprintf and the trailing null gordonb.7tw58@burditt.org (Gordon Burditt) - 2015-07-07 15:40 -0500
                Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-07 15:14 -0700
        Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 07:27 -0700
          Re: sprintf and the trailing null jt@toerring.de (Jens Thoms Toerring) - 2015-07-06 16:46 +0000
        Re: sprintf and the trailing null Keith Thompson <kst-u@mib.org> - 2015-07-06 07:56 -0700
  Re: sprintf and the trailing null Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-07-06 09:32 -0600
  Re: sprintf and the trailing null Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-06 08:37 -0700
    Re: sprintf and the trailing null Keith Thompson <kst-u@mib.org> - 2015-07-06 08:54 -0700
  Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 08:53 -0700
    Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 09:00 -0700
    Re: sprintf and the trailing null Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-06 17:14 +0100
      Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 09:24 -0700
        Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 09:31 -0700
  Re: sprintf and the trailing null Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2015-07-07 01:43 +0200
    Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 17:09 -0700
      Re: sprintf and the trailing null Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-07-06 21:08 -0600
        Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-06 21:29 -0700
        Re: sprintf and the trailing null Phil Carmody <pc+usenet@asdf.org> - 2015-07-08 20:24 +0300
          Re: sprintf and the trailing null "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-08 10:44 -0700
  Re: sprintf and the trailing null Les Cargill <lcargill99@comcast.com> - 2015-07-07 21:48 -0500

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