Re: Updating pointer with result of sprintf

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: Updating pointer with result of sprintf
Date	2017-11-28 16:32 +0000
Organization	A noiseless patient Spider
Message-ID	<871skitlcv.fsf@bsb.me.uk> (permalink)
References	<ovjd76$sbt$1@dont-email.me> <73dd9def-b2ac-49b6-9aa3-78c8350c86f1@googlegroups.com> <m2r2sibgnj.fsf@despina.home> <04ca6191-0c9f-4cfa-a881-002c66933fa0@googlegroups.com> <d105453b-64d4-44c5-9260-dea70eefb077@googlegroups.com>

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"Rick C. Hodgin" <rick.c.hodgin@gmail.com> writes:

> On Tuesday, November 28, 2017 at 10:24:08 AM UTC-5, Rick C. Hodgin wrote:
>> On Tuesday, November 28, 2017 at 9:51:44 AM UTC-5, Pascal J. Bourguignon wrote:
>> > One advantage of using indexing, is that it allows you to easily fill
>> > the buffer from right-to-left, when you want to dump readably values
>> > that are stored in little-endian order.  But using snprintf!
>> > 
>> >          snprintf(buf + sizeof(buf) - 1 - 2*i, 2, "%02x", src[i]);
>> 
>> Does snprintf() not put on the final \000 character?  I didn't know
>> that.  I could've used that many times. :-)  It would work for post-
>> processing inserts, all kinds of things.  I've always wound up using
>> sprintf() to a buffer, and then a separate memcpy() for the strlen(),
>> which ignores the trailing \000 character in the copy.  Very obtuse.
<snip>
> I see from the snprintf() documentation that it only doesn't write
> the trailing NULL if the generated string length is exactly the same
> as the length restriction imposed on the function call.

No, it writes a null (I prefer not to use the same name for the
character and the macro) in all cases except when n == 0.

<snip>
-- 
Ben.

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Thread

Updating pointer with result of sprintf Noob <root@127.0.0.1> - 2017-11-28 11:19 +0100
  Re: Updating pointer with result of sprintf bartc <bc@freeuk.com> - 2017-11-28 11:02 +0000
  Re: Updating pointer with result of sprintf jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-28 12:09 +0100
    Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-28 11:23 +0000
    Re: Updating pointer with result of sprintf Keith Thompson <kst-u@mib.org> - 2017-11-28 08:58 -0800
  Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-28 11:10 +0000
    Re: Updating pointer with result of sprintf Spiros Bousbouras <spibou@gmail.com> - 2017-11-28 16:51 +0000
      Re: Updating pointer with result of sprintf Keith Thompson <kst-u@mib.org> - 2017-11-28 09:24 -0800
      Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-29 00:33 +0000
        Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-29 00:36 +0000
        Re: Updating pointer with result of sprintf Spiros Bousbouras <spibou@gmail.com> - 2017-11-29 19:04 +0000
  Re: Updating pointer with result of sprintf "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-28 12:47 +0100
    Re: Updating pointer with result of sprintf "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-28 12:49 +0100
  Re: Updating pointer with result of sprintf scott@slp53.sl.home (Scott Lurndal) - 2017-11-28 14:19 +0000
    Re: Updating pointer with result of sprintf gazelle@shell.xmission.com (Kenny McCormack) - 2017-11-28 14:27 +0000
    Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-28 14:35 +0000
  Re: Updating pointer with result of sprintf "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-28 06:31 -0800
    Re: Updating pointer with result of sprintf "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-28 15:51 +0100
      Re: Updating pointer with result of sprintf "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-28 07:23 -0800
        Re: Updating pointer with result of sprintf "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-28 08:16 -0800
          Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-28 16:32 +0000
            Re: Updating pointer with result of sprintf "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-28 08:57 -0800
            Re: Updating pointer with result of sprintf "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-29 00:47 +0100
          Re: Updating pointer with result of sprintf "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-29 00:45 +0100
      Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-28 16:22 +0000
        Re: Updating pointer with result of sprintf Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-28 16:25 +0000
        Re: Updating pointer with result of sprintf "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-29 00:48 +0100
  Re: Updating pointer with result of sprintf Noob <root@127.0.0.1> - 2017-11-29 10:07 +0100
    Re: Updating pointer with result of sprintf Barry Schwarz <schwarzb@dqel.com> - 2017-11-29 09:18 -0800

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