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Groups > comp.lang.c > #147635
| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: One works, the other doesn't? |
| Date | 2019-11-05 23:24 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <qpssq3$3ee$4@dont-email.me> (permalink) |
| References | (2 earlier) <0EgwF.8082$kt1.6599@fx46.iad> <35717f02-8402-418e-acd0-ceec084d15de@googlegroups.com> <bVgwF.21715$FR8.19478@fx45.iad> <4986f18b-f4db-4d07-ae8b-b5ecf71bbe7b@googlegroups.com> <3thwF.58753$VR.56155@fx39.iad> |
On 05/11/2019 17:29, DFS wrote:
> On 11/5/2019 11:04 AM, Malcolm McLean wrote:
>> On Tuesday, 5 November 2019 15:52:48 UTC, DFS wrote:
>>> On 11/5/2019 10:45 AM, mark.bluemel@gmail.com wrote:
>>>> On Tuesday, 5 November 2019 15:34:32 UTC, DFS wrote:
>>>>
>>>>> printf("%.4s remove %d
>>>>> dupes\n",elapsedtime(start),arrsize-cnt);
>>>>
>>>> "%.4s" is a (slightly unusual) format specifier for a string.
>>>> It's a
>>>> totally unsuitable format specifier for a double value, which I think
>>>> is what elapsedtime() returns. I'd kind of expect it to fail, in some
>>>> unpredictable manner, as the printf routine tries to treat a double as
>>>> a pointer-to-char and disappears into some abyss or other.
>>>
>>>
>>> Dude! It's a format specifier for a double (elapsed time), but I
>>> inadvertently dropped the f (should be .4fs, where the s is short for
>>> seconds).
>>>
>>> This was causing my program to fail, and I didn't look closely enough at
>>> that line. Now I'm golden - I think.
>>>
>>> Thanks for spotting it!
>>>
>> If you use a good modern IDE, it will warn you when the format string
>> and the arguments don't match.
>
>
> I'm using geany and Tiny C Compiler (Windows). Neither one catches it
> (I wouldn't expect Geany to).
>
/Why/ are you using tcc? If you were developing on a tiny or ancient
computer, I could understand it. But gcc is a vastly better compiler,
especially during development. Run it with warnings enabled - not just
-Wall, but I'd recommend -Wextra as well, and perhaps "-pedantic" if you
are interested in portable code, as well as specifying the standard you
want (like "-std=gcc11" or "-std=c99").
> printf("%.4s remove %d dupes\n",elapsedtime(start),arrsize-cnt);
>
> tcc -Wall -o rand.exe random_strings_clc_final.c
> compilation finished successfully
>
>
> But gcc (on MSYS2) does:
>
> $ gcc -Wall -o rand.exe random_strings_clc_final.c
> random_strings_clc_final.c: In function ‘main’:
> random_strings_clc_final.c:132:16: warning: format ‘%s’ expects argument
> of type ‘char *’, but argument 2 has type ‘double’ [-Wformat=]
> 132 | printf("%.4s remove %d
> dupes\n",elapsedtime(start),arrsize-cnt);
> | ~~~^ ~~~~~~~~~~~~~~~~~~
> | | |
> | char * double
> | %.4f
>
>
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One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-03 17:39 -0500
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-04 00:20 +0000
Re: One works, the other doesn't? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-11-04 06:53 +0000
Re: One works, the other doesn't? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-04 09:45 -0500
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-05 10:34 -0500
Re: One works, the other doesn't? mark.bluemel@gmail.com - 2019-11-05 07:45 -0800
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-05 10:53 -0500
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-05 08:04 -0800
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-05 11:29 -0500
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-05 23:24 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-05 23:06 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-06 12:31 +1300
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-05 23:43 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-06 12:54 +1300
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-06 01:35 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-06 15:16 +1300
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-06 11:11 +0000
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-06 01:59 -0800
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-06 11:35 +0100
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-06 08:57 -0800
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-07 07:24 +1300
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-06 22:59 +0100
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-06 14:37 -0800
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 00:58 +0100
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-07 02:08 -0800
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 15:43 +0100
Re: One works, the other doesn't? Robert Wessel <robertwessel2@yahoo.com> - 2019-11-07 16:15 -0600
Re: One works, the other doesn't? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-11-10 20:01 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-11 15:26 +1300
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-11 12:37 +0100
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-07 07:21 +1300
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-06 10:39 -0800
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-07 07:47 +1300
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-07 08:14 +1300
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-06 12:30 -0800
Re: One works, the other doesn't? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-08 21:04 -0800
Re: One works, the other doesn't? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-11-09 01:37 -0800
Re: One works, the other doesn't? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-11-09 01:38 -0800
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-10 08:32 +1300
Re: One works, the other doesn't? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 16:09 -0800
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-29 11:33 +0100
Re: One works, the other doesn't? Öö Tiib <ootiib@hot.ee> - 2019-11-30 14:20 -0800
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-12-01 12:15 +1300
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-06 10:07 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-06 10:58 +0000
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 10:05 +0100
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-06 09:52 +0100
Re: One works, the other doesn't? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-11-06 00:56 -0800
Re: One works, the other doesn't? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-11-06 01:00 -0800
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-06 11:32 +0000
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-06 23:11 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-06 23:22 +0000
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 01:04 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 01:13 +0000
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 10:22 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 11:51 +0000
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 15:58 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 16:34 +0000
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-07 12:40 -0500
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 17:57 +0000
Re: One works, the other doesn't? Keith Thompson <kst-u@mib.org> - 2019-11-07 21:14 -0800
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-08 09:45 +0000
Re: One works, the other doesn't? Keith Thompson <kst-u@mib.org> - 2019-11-08 09:56 -0800
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-08 19:47 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-09 09:14 +1300
Re: One works, the other doesn't? Keith Thompson <kst-u@mib.org> - 2019-11-08 19:10 -0800
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-09 12:24 +0000
Like an old married couple... (Was: One works, the other doesn't?) gazelle@shell.xmission.com (Kenny McCormack) - 2019-11-08 20:25 +0000
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 19:58 +0100
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 19:31 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-08 08:56 +1300
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 20:06 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-08 09:21 +1300
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 21:20 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-08 10:28 +1300
Re: One works, the other doesn't? Bart <bc@freeuk.com> - 2019-11-07 22:35 +0000
Re: One works, the other doesn't? Ian Collins <ian-news@hotmail.com> - 2019-11-09 09:22 +1300
Re: One works, the other doesn't? jadill33@gmail.com - 2019-11-07 08:37 -0800
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-07 08:52 -0800
Re: One works, the other doesn't? jadill33@gmail.com - 2019-11-07 09:52 -0800
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-07 20:04 +0100
Re: One works, the other doesn't? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-08 19:50 -0800
Re: One works, the other doesn't? Bonita Montero <Bonita.Montero@gmail.com> - 2019-11-05 18:05 +0100
Re: One works, the other doesn't? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-11-05 09:28 -0800
Re: One works, the other doesn't? Bonita Montero <Bonita.Montero@gmail.com> - 2019-11-05 19:02 +0100
Re: One works, the other doesn't? David Brown <david.brown@hesbynett.no> - 2019-11-05 23:21 +0100
Re: One works, the other doesn't? Bonita Montero <Bonita.Montero@gmail.com> - 2019-11-06 18:36 +0100
Re: One works, the other doesn't? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-05 12:51 -0500
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-05 18:35 -0500
Re: One works, the other doesn't? Barry Schwarz <schwarzb@delq.com> - 2019-11-05 17:53 -0800
Re: One works, the other doesn't? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-11-06 09:33 -0500
Re: One works, the other doesn't? Barry Schwarz <schwarzb@delq.com> - 2019-11-05 13:36 -0800
Re: One works, the other doesn't? jak <nospam@please.ty> - 2019-11-07 10:17 +0100
Re: One works, the other doesn't? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-11-07 12:19 +0000
Re: One works, the other doesn't? jak <nospam@please.ty> - 2019-11-07 18:59 +0100
Re: One works, the other doesn't? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-11-08 00:02 +0000
Re: One works, the other doesn't? jak <nospam@please.ty> - 2019-11-20 10:54 +0100
Re: One works, the other doesn't? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-11-20 11:14 +0000
Re: One works, the other doesn't? jak <nospam@please.ty> - 2019-11-20 13:22 +0100
Re: One works, the other doesn't? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 15:54 -0800
Re: One works, the other doesn't? Keith Thompson <kst-u@mib.org> - 2019-11-20 08:42 -0800
Re: One works, the other doesn't? Manfred <noname@add.invalid> - 2019-11-21 18:56 +0100
Re: One works, the other doesn't? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-11-22 01:07 +0000
Re: One works, the other doesn't? Manfred <noname@add.invalid> - 2019-11-22 15:27 +0100
Re: One works, the other doesn't? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 15:47 -0800
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-07 18:41 -0500
Re: One works, the other doesn't? Bonita Montero <Bonita.Montero@gmail.com> - 2019-11-05 17:39 +0100
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-05 11:47 -0500
Re: One works, the other doesn't? Bonita Montero <Bonita.Montero@gmail.com> - 2019-11-05 17:54 +0100
Re: One works, the other doesn't? luser droog <luser.droog@gmail.com> - 2019-11-05 09:00 -0800
Re: One works, the other doesn't? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-08 21:02 -0800
Re: One works, the other doesn't? DFS <nospam@dfs.com> - 2019-11-09 02:09 -0500
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