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Re: PRI* considered harmful

Newsgroups comp.std.c
Subject Re: PRI* considered harmful
References (5 earlier) <lnhb6xzmbf.fsf@nuthaus.mib.org> <87zkkpef5z.fsf@once.weird.com> <iv5qd4$f26$1@dont-email.me> <87mxgpe84b.fsf@once.weird.com> <iv6qdm$ei8$1@dont-email.me>
From "Greg A. Woods" <woods@robohack.org>
Message-ID <878vs8dm52.fsf@once.weird.com> (permalink)
Date 2011-07-08 23:05 -0700

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James Kuyper <jameskuyper@verizon.net> writes:
>
> On 07/07/2011 11:58 PM, Greg A. Woods wrote:
>> James Kuyper <jameskuyper@verizon.net> writes:
>>>
>>> The right way to warn about mismatches: only warn when there's an actual
>>> mismatch.
>> 
>> It is an "actual" mis-match -- at least if you intend your code to be
>> portable.
>
> For every conforming implementation of C, PRI32d must be a correct match
> to whichever type int32_t represents in that implementation. While
> implementations are permitted to issue diagnostics for any reason they
> like ("warning: identifiers containing 'z' make me feel fuzzy!"), an
> implementation which diagnoses the correct match that PRI32d must have
> with int32_t has low QoI because it's wasting the developer's time.

I'm explicitly not talking about the ideal world where every
implementation is conforming!

This is an issue of application in the real-world, of helping to make
real-world code work in real-world environments.


> Then why are they using int32_t? They only need the PRI* macros if they
> choose to use the new size-named types.

Because people love to use new features, but when those features are not
really well documented, and when they can easily lead to such problems,
those features might cause more harm than good.  Read some real code
(e.g. do some internet searches on *PRI* and *FMT* to find examples) and
see for yourself.


>>> Well, of course not. For that you use
>>> 	printf("seconds since epoch:%.0f\n", difftime(value,epoch));
>> 
>> Decades of unix tradition flushed down the drain by C99.  :-)
>
> What tradition are you talking about?

The tradition of course that time_t is, always has been, and always will
be, an _integer_ number of seconds since the epoch.

> What you've specified is not something I can see any point in printing
> out,

Assumptions, assumptions, assumptions!  You know what they say about
assumptions!  :-)

-- 
						Greg A. Woods
						RoboHack

<woods@robohack.ca>     living on the edge      http://www.robohack.ca/

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PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-06 19:58 -0700
  Re: PRI* considered harmful William Ahern <william@wilbur.25thandClement.com> - 2011-07-06 20:38 -0700
    Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-06 22:26 -0700
      Re: PRI* considered harmful Jens Gustedt <Jens.Gustedt@loria.fr> - 2011-07-07 08:52 +0200
        Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-07 14:11 -0700
          Re: PRI* considered harmful Jens Gustedt <Jens.Gustedt@loria.fr> - 2011-07-08 11:58 +0200
        Re: PRI* considered harmful lawrence.jones@siemens.com - 2011-07-07 17:58 -0400
          Re: PRI* considered harmful Jens Gustedt <Jens.Gustedt@loria.fr> - 2011-07-08 12:02 +0200
      Re: PRI* considered harmful lawrence.jones@siemens.com - 2011-07-07 17:57 -0400
        Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-07 15:42 -0700
          Re: PRI* considered harmful lawrence.jones@siemens.com - 2011-07-08 08:56 -0400
  Re: PRI* considered harmful James Kuyper <jameskuyper@verizon.net> - 2011-07-07 06:36 -0400
    Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-07 12:59 -0700
      Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-07 14:12 -0700
        Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-07 15:49 -0700
          Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-07 16:46 -0700
            Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-07 18:26 -0700
              Re: PRI* considered harmful James Kuyper <jameskuyper@verizon.net> - 2011-07-07 22:35 -0400
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-07 20:58 -0700
                Re: PRI* considered harmful Wojtek Lerch <wojtek_l@yahoo.ca> - 2011-07-08 00:28 -0400
                Re: PRI* considered harmful James Kuyper <jameskuyper@verizon.net> - 2011-07-08 07:41 -0400
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-08 23:05 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 00:50 -0700
                Re: [incorrectly implementd] PRI* considered harmful James Kuyper <jameskuyper@verizon.net> - 2011-07-09 06:38 -0400
                Re: PRI* considered harmful Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2011-07-09 21:07 +0200
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-08 09:52 -0700
              Re: PRI* considered harmful Richard Kettlewell <rjk@greenend.org.uk> - 2011-07-08 11:45 +0100
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-08 23:14 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 00:47 -0700
                Re: PRI* considered harmful Richard Kettlewell <rjk@greenend.org.uk> - 2011-07-09 10:51 +0100
                Re: PRI* considered harmful James Kuyper <jameskuyper@verizon.net> - 2011-07-09 06:43 -0400
              Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-08 09:49 -0700
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-08 23:24 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 00:45 -0700
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-09 16:18 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 18:57 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-13 09:37 -0700
                Re: PRI* considered harmful James Kuyper <jameskuyper@verizon.net> - 2011-07-09 06:46 -0400
                Re: PRI* considered harmful Harald van Dijk <truedfx@gmail.com> - 2011-07-09 08:09 -0700
                Re: PRI* considered harmful Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-07-11 16:00 +0300
                Re: PRI* considered harmful Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2011-07-09 20:59 +0200
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 12:22 -0700
                Re: PRI* considered harmful Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2011-07-09 21:32 +0200
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 12:54 -0700
                Re: PRI* considered harmful Marcin Grzegorczyk <mgrzegor@poczta.onet.pl> - 2011-07-09 23:39 +0200
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-09 16:56 -0700
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-09 16:52 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 18:53 -0700
                Re: PRI* considered harmful Jens Gustedt <Jens.Gustedt@loria.fr> - 2011-07-10 14:12 +0200
                Re: PRI* considered harmful Marcin Grzegorczyk <mgrzegor@poczta.onet.pl> - 2011-07-11 20:22 +0200
                Re: PRI* considered harmful Jens Gustedt <Jens.Gustedt@loria.fr> - 2011-07-10 13:57 +0200
                Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-09 16:49 -0700
                Re: PRI* considered harmful Jens Schweikhardt <usenet@schweikhardt.net> - 2011-07-19 19:28 +0000
      Re: PRI* considered harmful Tim Rentsch <txr@alumni.caltech.edu> - 2011-07-07 14:13 -0700
  Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 01:04 -0700
    Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-09 17:23 -0700
      Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-09 19:03 -0700
        Re: PRI* considered harmful Marcin Grzegorczyk <mgrzegor@poczta.onet.pl> - 2011-07-11 20:40 +0200
          Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-11 11:56 -0700
            Re: PRI* considered harmful Marcin Grzegorczyk <mgrzegor@poczta.onet.pl> - 2011-07-11 21:40 +0200
              Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-11 13:16 -0700
                Re: PRI* considered harmful Marcin Grzegorczyk <mgrzegor@poczta.onet.pl> - 2011-07-11 23:29 +0200
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-11 14:46 -0700
              Re: PRI* considered harmful "Greg A. Woods" <woods@robohack.org> - 2011-07-12 22:18 -0700
                Re: PRI* considered harmful Keith Thompson <kst-u@mib.org> - 2011-07-13 09:00 -0700
  Re: PRI* considered harmful Richard Kettlewell <rjk@greenend.org.uk> - 2011-07-09 20:30 +0100

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