Groups | Search | Server Info | Login | Register

Groups > comp.lang.c > #398044

Re: Small challenge: sort names

From cross@spitfire.i.gajendra.net (Dan Cross)
Newsgroups comp.lang.c
Subject Re: Small challenge: sort names
Date 2026-04-27 20:43 +0000
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <10sohpc$444$1@reader1.panix.com> (permalink)
References <10r4h6o$396qn$1@dont-email.me> <10soe78$2kmgo$1@dont-email.me> <10soe9m$2l223$1@dont-email.me> <10sof6k$2l43i$1@kst.eternal-september.org>

Show all headers | View raw

In article <10sof6k$2l43i$1@kst.eternal-september.org>,
Keith Thompson  <Keith.S.Thompson+u@gmail.com> wrote:
>"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
>> On 4/27/2026 12:42 PM, Chris M. Thomasson wrote:
>[...]
>>> Fwiw, I only use '\0' for the null terminator in strings, not for
>>> pointers...
>
>I'm not sure why that's worth mentioning.  The only reason I can
>think of to use '\0' for pointers is deliberate obfuscation, or
>*maybe* testing how a compiler handles it.

Some time ago, a rather famous production outage at Google was
the result of something very similar.  The author wrote,

	ptr->some_bool = false;

where what was meant was,

	*ptr->some_bool = false;

Here, `some_bool` was `bool *some_bool`.  Perfectly legal, of
course: `false` was just a macro expanding to the integer
constant 0, which in pointer context is a null pointer constant,
thus setting `some_bool` to the null pointer.  But clearly what
was meant was to assign false to the actual boolean.  Oops.

At the time, the compiler (gcc) did not emit a diagnostic for
this, but `clang` did.  The build system was quickly changed to
invoke both; showing combined diagnostics from both compilers,
but keeping only the object file emitted by gcc (as I understand
it, Google has since switched to using `clang` as the default
compiler in its monorepo).

This, and similar incidents, are one reason I greatly prefer
domain-specific constructs (e.g, '\0' for character data instead
of plain ol' 0) and explicit comparisons (`if (ptr != NULL)` vs
`if (ptr)`).  Over time and at large enough scale, these things
really do start to matter.

>> Or NUL for strings?
>
>NUL is a name for the null character, but there's no such identifier
>in the C standard language or library.

FWIW, observation over some time makes me think that the person
to whom you are responding is driving with an engine that is not
quite firing on all cylinders.  His posts are usually non
sequiturs, and he tends to reply to himself often.  He's not
offensive or anything, so I haven't plonked him, but I try to
refrain from engaging with him.

	- Dan C.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Re: Small challenge: sort names Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-04-25 13:31 -0700
  Re: Small challenge: sort names Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-04-25 15:12 -0700
    Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-26 04:13 +0200
      Re: Small challenge: sort names Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-04-25 19:50 -0700
        Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-26 05:28 +0200
          Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-26 12:08 +0200
            Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-26 18:16 +0200
              Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-26 19:37 +0200
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-27 02:17 +0200
                Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-27 09:19 +0200
              Re: Small challenge: sort names scott@slp53.sl.home (Scott Lurndal) - 2026-04-26 17:47 +0000
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-27 02:33 +0200
                Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-27 09:34 +0200
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-27 12:35 +0200
                Re: Small challenge: sort names Bart <bc@freeuk.com> - 2026-04-27 13:28 +0100
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-27 17:02 +0200
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-27 17:36 +0200
                Re: Small challenge: sort names scott@slp53.sl.home (Scott Lurndal) - 2026-04-27 16:18 +0000
                Re: Small challenge: sort names Michael S <already5chosen@yahoo.com> - 2026-04-27 11:42 +0300
                Re: Small challenge: sort names scott@slp53.sl.home (Scott Lurndal) - 2026-04-27 16:27 +0000
                Assembler verb choice (Was: Small challenge: sort names) gazelle@shell.xmission.com (Kenny McCormack) - 2026-04-28 12:59 +0000
                Re: Assembler verb choice (Was: Small challenge: sort names) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-28 16:26 +0200
                Re: Small challenge: sort names "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-04-27 12:45 -0700
        Re: Small challenge: sort names "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-04-27 12:42 -0700
          Re: Small challenge: sort names "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-04-27 12:43 -0700
            Re: Small challenge: sort names Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-04-27 12:59 -0700
              Re: Small challenge: sort names "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-04-27 13:26 -0700
              Re: Small challenge: sort names cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-27 20:43 +0000
                Re: Small challenge: sort names "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-04-27 17:30 -0700
                Re: Small challenge: sort names Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-04-27 19:15 -0700
                Re: Small challenge: sort names gazelle@shell.xmission.com (Kenny McCormack) - 2026-04-28 12:01 +0000
                Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-28 08:35 +0200
                Re: Small challenge: sort names cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-28 13:27 +0000
                Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-28 15:59 +0200
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-28 16:49 +0200
                Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-28 17:25 +0200
                Re: Small challenge: sort names Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-04-28 23:46 +0200
                Re: Small challenge: sort names cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-28 18:12 +0000
                Re: Small challenge: sort names David Brown <david.brown@hesbynett.no> - 2026-04-28 20:28 +0200
    Re: Small challenge: sort names vallor <vallor@vallor.earth> - 2026-04-28 13:45 +0000

csiph-web