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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: int * vs char * |
| Date | 2011-06-25 09:28 +1200 |
| Message-ID | <96kdsvFb9tU7@mid.individual.net> (permalink) |
| References | (3 earlier) <itsfv5$e9l$1@dont-email.me> <96evn3FmtvU8@mid.individual.net> <ittpbt$k92$1@dont-email.me> <ln39j1gzu0.fsf@nuthaus.mib.org> <iu2p8p$ubl$1@dont-email.me> |
On 06/25/11 07:39 AM, Shao Miller wrote:
> On 6/22/2011 20:23, Keith Thompson wrote:
>
>> The fact that I've never heard of anyone implementing something like
>> this suggests (though not strongly) that there's no demand for it.
>>
>
> Suppose you've a program loaded into memory via a serial line. Suppose
> the program is loaded into writable memory (that seems pretty likely).
> Suppose the program offers a CLI. Suppose a user can rename commands or
> variables, or redefine preset scripts.
A recipe for disaster! What happens if a new name is linger than the old?
> Yes, all of these could be done
> cleanly (in my opinion) via 'static' 'char[]'s, but it can be more
> convenient for some people to simply type the string literal right into
> some spot in the source code where it's used and forget about coming up
> with a meaningful (and possibly redundant) identifier, i.e.
> 'csz_Hello__world___And_how_are_you__today_'
Yuck, what a contrived example! As you say, there is a method that does
not use undefined behaviour.
>> I suspect that the vast majority of code that attempts to modify
>> string literals does so as the result of bugs.
>
> That seems probable to me, too.
>
>> A lot more code
>> uses string literals in contexts that don't treat them as const,
>> but doesn't actually try to modify them; for example:
>>
>> void func(char *s) {
>> printf("In func(), s = \"%s\"\n");
>> }
>>
>> ...
>>
>> func("hello");
>>
>> In short, I think the issue is not that anyone wants to modify
>> string literals;
>
> For the right use case, I would.
>
>> it's that making them const would break existing
>> code that *doesn't* actually modify string literals.
>>
>> (Stroustrup was able to do this in C++ because there was no existing
>> C++ code before he invented the language.)
>>
>
> Well doesn't 'const' "come from" C++, anyway?
No, it's just used properly there!
> And why isn't there a write-only counterpart, for symmetry, such as a
> memory-mapped port that mustn't be read from?
That case isn't uncommon in embedded systems (watchdog reset being a
common example). However reading is generally harmless.
> And during very early development (and Usenet code examples), can it be
> pleasant to avoid 'const' concerns altogether and then to analyze and
> refine, gradually sprinkling 'const' in where appropriate? I don't
> advocate this, but imagine that some folks might get "stuck" in
> "analysis paralysis" if they had to think 'const'ness through at every
> corner. I could be mistaken.
Not really, if you don't know whether the function you are writing will
modify its arguments, you are big trouble!
--
Ian Collins
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
int * vs char * yugandhar <nospam@nospam.com> - 2011-06-21 21:49 +0000
Re: int * vs char * John Gordon <gordon@panix.com> - 2011-06-21 21:58 +0000
Re: int * vs char * "Morris Keesan" <mkeesan@post.harvard.edu> - 2011-06-21 20:25 -0400
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-22 09:59 +1200
Re: int * vs char * Ike Naar <ike@sverige.freeshell.org> - 2011-06-21 22:18 +0000
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-06-21 18:34 -0500
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-21 15:42 -0700
Re: int * vs char * Noob <root@127.0.0.1> - 2011-06-22 10:28 +0200
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-06-22 05:23 -0500
Re: int * vs char * James Kuyper <jameskuyper@verizon.net> - 2011-06-22 06:25 -0400
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-23 07:56 +1200
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-06-22 18:12 -0500
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-23 10:23 +1200
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-22 17:23 -0700
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-23 12:54 +1200
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-22 18:18 -0700
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-23 13:23 +1200
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-06-24 15:39 -0400
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-25 09:28 +1200
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-24 14:58 -0700
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-25 10:06 +1200
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-06-26 15:44 -0500
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-24 14:29 -0700
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-25 09:36 +1200
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-06-26 16:24 -0500
Re: int * vs char * Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-25 08:39 -0700
Re: int * vs char * gordonb.5qick@burditt.org (Gordon Burditt) - 2011-06-22 23:49 -0500
Re: int * vs char * Stephen Sprunk <stephen@sprunk.org> - 2011-06-22 11:31 -0500
Re: int * vs char * gordonb.idn9q@burditt.org (Gordon Burditt) - 2011-06-23 00:45 -0500
Re: int * vs char * pacman@kosh.dhis.org (Alan Curry) - 2011-06-23 20:08 +0000
Re: int * vs char * Stephen Sprunk <stephen@sprunk.org> - 2011-06-23 22:40 -0500
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-24 15:46 +1200
Re: int * vs char * Stephen Sprunk <stephen@sprunk.org> - 2011-06-24 09:24 -0500
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-07-04 18:00 -0400
Re: int * vs char * Dr Nick <3-nospam@temporary-address.org.uk> - 2011-07-05 07:45 +0100
Re: int * vs char * Harald van Dijk <truedfx@gmail.com> - 2011-07-05 10:39 -0700
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-07-05 14:09 -0400
Re: int * vs char * Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-07-07 21:56 +0300
Re: int * vs char * Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-07-08 02:46 +0300
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-07-07 22:26 -0400
Re: int * vs char * Stephen Sprunk <stephen@sprunk.org> - 2011-07-07 22:41 -0500
Re: int * vs char * "Joel C. Salomon" <joelcsalomon@gmail.com> - 2011-07-05 15:32 -0400
Re: int * vs char * Shao Miller <sha0.miller@gmail.com> - 2011-07-06 09:58 -0400
Re: int * vs char * Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-23 01:02 -0700
Re: int * vs char * Ian Collins <ian-news@hotmail.com> - 2011-06-23 20:11 +1200
Re: int * vs char * Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-25 09:23 -0700
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-25 12:37 -0700
Re: int * vs char * Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-27 11:40 -0700
Re: int * vs char * Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-21 21:46 -0400
Re: int * vs char * "Kleuskes & Moos" <kleuske@xs4all.nl> - 2011-06-22 10:06 -0700
Re: int * vs char * Keith Thompson <kst-u@mib.org> - 2011-06-22 13:06 -0700
Re: int * vs char * "Kleuskes & Moos" <kleuske@xs4all.nl> - 2011-06-22 13:29 -0700
Re: int * vs char * Stephen Sprunk <stephen@sprunk.org> - 2011-06-21 21:29 -0500
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