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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: setting pointers to NULL and testing question. |
| Date | 2016-06-21 11:28 -0700 |
| Organization | None to speak of |
| Message-ID | <lnlh1yqtui.fsf@kst-u.example.com> (permalink) |
| References | (2 earlier) <njpk7n$78g$1@dont-email.me> <kfneg7x4zn3.fsf@x-alumni2.alumni.caltech.edu> <njt68h$nh6$1@dont-email.me> <njuj48$461$1@dont-email.me> <kfnziqk1kys.fsf@x-alumni2.alumni.caltech.edu> |
Tim Rentsch <txr@alumni.caltech.edu> writes:
> James Kuyper <jameskuyper@verizon.net> writes:
[...]
>> Counter:
>> If an uninitialized variable is used before being initialized, in a way
>> that the compiler can't catch - it will cause problems. [...]
>
> There are no such cases. A conservative analysis can catch every
> situation where a variable might be used before being given an
> initial value, provided of course that we are willing to tolerate
> some false positives.
The degenerate algorithm is to flag every variable reference with
a warning that it might be used without having been initialized.
This will catch all cases where variables are used before being
initialized, but with enough false positives to make it useless.
A more nearly reasonable approach is to flag any use where the
compiler can't *prove* that the variable has been initialized.
This avoids the most obvious false positives (assuming a reasonably
clever compiler), but it's still likely to produce too many
spurious warnings -- unless, as you suggest downthread, there's
an option to say "gimme those spurious warnings anyway, I want to
see *everything*".
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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setting pointers to NULL and testing question. G G <gdotone@gmail.com> - 2016-06-12 16:21 -0700
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-13 00:50 +0100
Re: setting pointers to NULL and testing question. G G <gdotone@gmail.com> - 2016-06-12 17:03 -0700
Re: setting pointers to NULL and testing question. Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-06-12 20:25 -0600
Re: setting pointers to NULL and testing question. James Kuyper <jameskuyper@verizon.net> - 2016-06-12 22:57 -0400
Re: setting pointers to NULL and testing question. Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-06-13 10:03 -0600
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-15 14:43 -0700
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-13 08:06 -0700
Re: setting pointers to NULL and testing question. Richard Damon <Richard@Damon-Family.org> - 2016-06-16 08:27 -0400
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-16 06:27 -0700
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-16 07:31 -0700
Re: setting pointers to NULL and testing question. Richard Damon <Richard@Damon-Family.org> - 2016-06-18 13:39 -0400
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-18 11:37 -0700
Re: setting pointers to NULL and testing question. Richard Damon <Richard@Damon-Family.org> - 2016-06-18 17:17 -0400
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-18 17:22 -0700
Re: setting pointers to NULL and testing question. James Kuyper <jameskuyper@verizon.net> - 2016-06-13 14:10 -0400
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-13 11:28 -0700
Re: setting pointers to NULL and testing question. Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-06-13 12:31 -0600
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-12 19:38 -0700
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-13 07:35 +0100
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-13 11:40 +0100
Re: setting pointers to NULL and testing question. BartC <bc@freeuk.com> - 2016-06-13 11:56 +0100
Re: setting pointers to NULL and testing question. Martin Shobe <mashobe9@gmail.com> - 2016-06-13 06:22 -0500
Re: setting pointers to NULL and testing question. BartC <bc@freeuk.com> - 2016-06-13 12:39 +0100
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-13 15:22 +0100
Re: setting pointers to NULL and testing question. BartC <bc@freeuk.com> - 2016-06-13 17:34 +0100
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-13 19:31 +0100
Re: setting pointers to NULL and testing question. BartC <bc@freeuk.com> - 2016-06-13 20:17 +0100
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-13 12:47 -0700
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-15 16:44 -0700
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-15 17:20 -0700
Re: setting pointers to NULL and testing question. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-06-13 04:01 -0700
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-16 12:57 -0700
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-13 12:18 +0100
Re: setting pointers to NULL and testing question. David Brown <david.brown@hesbynett.no> - 2016-06-13 14:01 +0200
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-13 14:15 +0100
Re: setting pointers to NULL and testing question. David Brown <david.brown@hesbynett.no> - 2016-06-13 15:37 +0200
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-13 14:48 +0100
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-13 15:43 +0100
Re: setting pointers to NULL and testing question. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-06-12 17:54 -0700
Re: setting pointers to NULL and testing question. John Bode <jfbode1029@gmail.com> - 2016-06-14 08:36 -0700
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-14 16:41 +0100
Re: setting pointers to NULL and testing question. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-06-14 09:01 -0700
Re: setting pointers to NULL and testing question. "James R. Kuyper" <jameskuyper@verizon.net> - 2016-06-14 13:25 -0400
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-14 10:48 -0700
Re: setting pointers to NULL and testing question. Ian Collins <ian-news@hotmail.com> - 2016-06-15 08:24 +1200
Re: setting pointers to NULL and testing question. "James R. Kuyper" <jameskuyper@verizon.net> - 2016-06-14 16:57 -0400
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-14 14:29 -0700
Re: setting pointers to NULL and testing question. BartC <bc@freeuk.com> - 2016-06-14 22:41 +0100
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-14 15:16 -0700
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-15 00:25 +0100
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-14 16:58 -0700
Re: setting pointers to NULL and testing question. David Brown <david.brown@hesbynett.no> - 2016-06-15 09:28 +0200
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-15 09:57 -0700
Re: setting pointers to NULL and testing question. David Brown <david.brown@hesbynett.no> - 2016-06-15 09:23 +0200
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-15 08:35 +0100
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-15 08:37 +0100
Re: setting pointers to NULL and testing question. David Brown <david.brown@hesbynett.no> - 2016-06-15 10:42 +0200
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-15 13:28 +0100
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-15 11:41 -0700
Re: setting pointers to NULL and testing question. raltbos@xs4all.nl (Richard Bos) - 2016-06-15 19:43 +0000
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-15 13:09 -0700
Re: setting pointers to NULL and testing question. David Brown <david.brown@hesbynett.no> - 2016-06-15 22:31 +0200
Re: setting pointers to NULL and testing question. Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-06-15 17:11 -0400
Re: setting pointers to NULL and testing question. raltbos@xs4all.nl (Richard Bos) - 2016-06-18 20:44 +0000
Re: setting pointers to NULL and testing question. Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-06-18 17:20 -0400
Re: setting pointers to NULL and testing question. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-06-14 23:22 -0700
Re: setting pointers to NULL and testing question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-15 13:23 +0100
Re: setting pointers to NULL and testing question. John Bode <jfbode1029@gmail.com> - 2016-06-20 13:36 -0700
Re: setting pointers to NULL and testing question. Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-06-14 14:59 -0400
Re: setting pointers to NULL and testing question. "James R. Kuyper" <jameskuyper@verizon.net> - 2016-06-14 15:17 -0400
Re: setting pointers to NULL and testing question. Richard Heathfield <rjh@cpax.org.uk> - 2016-06-14 20:25 +0100
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-15 19:48 -0700
Re: setting pointers to NULL and testing question. Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-06-15 23:25 -0400
Re: setting pointers to NULL and testing question. James Kuyper <jameskuyper@verizon.net> - 2016-06-16 12:11 -0400
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-16 09:25 -0700
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-16 21:46 -0700
Re: setting pointers to NULL and testing question. Gareth Owen <gwowen@gmail.com> - 2016-06-17 06:13 +0100
Re: setting pointers to NULL and testing question. Robert Wessel <robertwessel2@yahoo.com> - 2016-06-17 02:03 -0500
Re: setting pointers to NULL and testing question. Martin Shobe <mashobe9@gmail.com> - 2016-06-17 07:07 -0500
Re: setting pointers to NULL and testing question. supercat@casperkitty.com - 2016-06-17 03:18 -0700
Re: setting pointers to NULL and testing question. James Kuyper <jameskuyper@verizon.net> - 2016-06-17 09:16 -0400
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-21 11:03 -0700
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-21 10:58 -0700
Re: setting pointers to NULL and testing question. Keith Thompson <kst-u@mib.org> - 2016-06-21 11:28 -0700
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-07-18 08:24 -0700
Re: setting pointers to NULL and testing question. Tim Rentsch <txr@alumni.caltech.edu> - 2016-06-16 21:39 -0700
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