Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #176418

Re: Dymamic arrays: memory management and naming

From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.lang.c
Subject Re: Dymamic arrays: memory management and naming
Date 2023-09-25 23:42 -0700
Organization A noiseless patient Spider
Message-ID <86jzsdigek.fsf@linuxsc.com> (permalink)
References (5 earlier) <KZf6tlV2s29qC6sCU@bongo-ra.co> <20230924081911.947@kylheku.com> <20230925155845.139@kylheku.com> <86sf71itgt.fsf@linuxsc.com> <20230925190228.732@kylheku.com>

Show all headers | View raw

Kaz Kylheku <864-117-4973@kylheku.com> writes:

> On 2023-09-26, Tim Rentsch <tr.17687@z991.linuxsc.com> wrote:
>
>> Kaz Kylheku <864-117-4973@kylheku.com> writes:
>>
>>> On 2023-09-24, Kaz Kylheku <864-117-4973@kylheku.com> wrote:
>>>
>>>> h only makes sense if you're passing a signed argument and want it
>>>> printed as unsigned.  Say we have 16 bit short and 32 bit int.
>>>> Then "%u"/(short) -1 will print as 429496725, whereas "%hu"/(short) -1
>>>> will obtain the desired 65535.
>>>
>>> There is something I had neglected to mention:  the use of h for
>>> portability
>>>
>>> If we have "%u" paired with an unsigned short, argument we have a
>>> mismatch on a large number of platforms, where unsigned short
>>> promotes to int.  The %u specifier wants unsigned int.
>>
>> A %u conversion specification is always okay for an unsigned
>> short argument, regardless of whether the argument promotes to
>> int or to unsigned int.
>>
>> Reading an integer-typed variadic
>> argument with the corresponding type of the other signedness
>> is allowed when the argument value is representable in both
>> types, which it always will be in this case even if unsigned
>> short promotes to int.
>
> OK, I see how that is derived.  printf is now described as if using
> va_arg to extract the promoted type of the conversion specifier's
> type, and then converting the promoted type to the the specifier's
> type (which can hardly be done in any other way).
>
> C99 didn't have this, only "If any argument is not the correct type
> for the corresponding conversion specification, the behavior is
> undefined."

Please see my response to the parallel post by Keith Thompson.

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

Thread

Dymamic arrays: memory management and naming Anton Shepelev <anton.txt@gmail.moc> - 2023-09-09 13:23 +0300
  Re: Dymamic arrays: memory management and naming Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-09 03:56 -0700
  Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-09 15:06 +0000
  Re: Dymamic arrays: memory management and naming scott@slp53.sl.home (Scott Lurndal) - 2023-09-09 15:44 +0000
  Re: Dymamic arrays: memory management and naming Spiros Bousbouras <spibou@gmail.com> - 2023-09-10 17:57 +0000
    Re: Dymamic arrays: memory management and naming Anton Shepelev <anton.txt@gmail.moc> - 2023-09-10 23:49 +0300
      Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-10 21:25 +0000
  Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-12 16:07 -0700
    Re: Dymamic arrays: memory management and naming Anton Shepelev <anton.txt@gmail.moc> - 2023-09-17 00:44 +0300
  Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-17 16:51 -0700
    Re: Dymamic arrays: memory management and naming Anton Shepelev <anton.txt@gmail.moc> - 2023-09-19 01:10 +0300
      Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-19 07:58 -0700
      Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-19 10:33 -0700
        Re: Dymamic arrays: memory management and naming Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-19 15:08 -0700
          Re: Dymamic arrays: memory management and naming "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-09-19 15:35 -0700
          Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-19 22:49 +0000
            Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-19 22:30 -0700
              Re: Dymamic arrays: memory management and naming Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-20 02:46 -0700
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-20 07:06 -0700
              Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-20 21:03 +0000
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 14:08 -0700
                Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-25 21:27 +0000
          Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-19 22:17 -0700
        Re: Dymamic arrays: memory management and naming Anton Shepelev <anton.txt@gmail.moc> - 2023-09-24 00:39 +0300
          Re: Dymamic arrays: memory management and naming Blue-Maned_Hawk <bluemanedhawk@invalid.invalid> - 2023-09-23 21:48 +0000
          Re: Dymamic arrays: memory management and naming James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-09-24 00:15 -0400
          Re: Dymamic arrays: memory management and naming Spiros Bousbouras <spibou@gmail.com> - 2023-09-24 11:48 +0000
            Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-24 16:08 +0000
              Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 13:21 -0700
                Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-25 21:06 +0000
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 18:43 -0700
              Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-25 23:14 +0000
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 19:00 -0700
                Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-26 02:38 +0000
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 23:42 -0700
                Re: Dymamic arrays: memory management and naming Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-25 19:38 -0700
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 23:41 -0700
                Re: Dymamic arrays: memory management and naming Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-26 02:42 -0700
                Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-03 03:29 -0700
            Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-24 16:11 +0000
            Re: Dymamic arrays: memory management and naming James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-09-24 12:28 -0400
              Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-24 17:10 +0000
                Re: Dymamic arrays: memory management and naming James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-09-24 13:56 -0400
            Re: Dymamic arrays: memory management and naming Phil Carmody <pc+usenet@asdf.org> - 2023-09-30 13:50 +0300
              Re: Dymamic arrays: memory management and naming Spiros Bousbouras <spibou@gmail.com> - 2023-10-01 17:43 +0000
          Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 09:21 -0700
            Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-25 18:06 +0000
              Re: Dymamic arrays: memory management and naming Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-25 15:24 -0700
                Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-25 23:49 +0000
                Re: Dymamic arrays: memory management and naming Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-26 00:07 +0000

csiph-web