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| From | pacman@kosh.dhis.org (Alan Curry) |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: C scope and struct definitions |
| Date | 2012-06-23 22:06 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <js5ekh$lug$1@speranza.aioe.org> (permalink) |
| References | <mYGdnXsGt41dNnnSnZ2dnUVZ_u-dnZ2d@bestweb.net> <js2buv$evv$1@dont-email.me> <js2s92$35s$1@speranza.aioe.org> <js32rk$siv$1@dont-email.me> |
In article <js32rk$siv$1@dont-email.me>,
Eric Sosman <esosman@ieee-dot-org.invalid> wrote:
>On 6/22/2012 6:40 PM, Alan Curry wrote:
>>
>> But is the compiler right for a real reason, or is it just a continuation of
>> a historical accident? Why would you ever want this behavior?
>
> The Rationale sheds no light my tired old eyes can see. You
>are welcome to read it for yourself. (Also, if you think the
>normative text of the formal definition of the C language does not
>qualify as "a real reason," well ...)
The standard was supposed to codify existing practice. A real reason would
have to come from before standardization. Was there a real reason for the
existence of such a small, useless scope?
>
>> I don't even see why you'd ever want any scope for a struct type other than
>> "from here to the end of the file". Types are global things.
>
> Say, what?
>
> void f(void) {
> static const struct foo {
> const char *roman;
> int decimal;
> } table[] = { { "I", 1 }, { "II", 2 }, ... };
> ...
> }
>
> void g(void) {
> struct foo {
> double payload;
> struct foo *next;
> } *head, *p, *q;
> ...
> }
>
>Do you seriously maintain that these two `struct foo' types
>should conflict with each other? If so, why? Explain why you
>feel it is Wrong for a function to declare and use its own
>private type for its own purposes, and why f() should have to
>worry about what g() does in the privacy of its own block.
I don't think we'd be losing anything if those declarations were simply
illegal. Declare your structs before your functions. They aren't variables.
A struct describes the procedure for interpreting bits in memory. As a
procedure description, it's more like a function than a variable. It doesn't
occupy memory itself, so it doesn't have a lifetime that can end when the
function call ends. Putting it inside the function gives you nothing.
If you really have two different structs with the same name in one program,
you should want to be warned about it. It's a sign that you should either
merge them (if they are different representations of the same concept) or
rename them.
Variables, functions, and constant data are all defined with reference to
types. Types are the most fundamental entities in a program. They deserve
globally unique names.
--
Alan Curry
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C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-22 13:30 -0400
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-22 14:02 -0400
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-22 22:40 +0000
Re: C scope and struct definitions Ben Pfaff <blp@cs.stanford.edu> - 2012-06-22 15:47 -0700
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-22 20:32 -0400
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-23 22:06 +0000
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-23 16:18 -0700
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-25 10:19 -0400
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-25 11:51 -0700
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-23 19:54 -0400
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-24 00:56 +0000
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-23 21:48 -0400
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-24 06:03 +0000
Re: C scope and struct definitions nick_keighley_nospam@hotmail.com - 2012-06-25 00:05 -0700
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-23 19:25 -0700
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-24 05:40 +0000
Re: C scope and struct definitions Jens Gustedt <jens.gustedt@loria.fr> - 2012-06-24 10:47 +0200
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-24 11:00 -0700
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-25 03:53 +0000
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-25 01:14 -0400
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-24 22:38 -0700
Re: C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-25 11:03 -0400
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-26 20:08 +0000
Re: C scope and struct definitions Jens Gustedt <jens.gustedt@loria.fr> - 2012-06-26 23:21 +0200
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-26 21:47 +0000
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-26 18:05 -0400
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-26 16:45 -0700
Re: C scope and struct definitions Jens Gustedt <jens.gustedt@loria.fr> - 2012-06-27 08:26 +0200
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-27 00:01 -0700
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-27 06:57 -0400
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-27 15:00 -0400
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-27 14:48 -0700
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-27 16:14 -0700
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-29 09:36 -0700
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-27 16:27 -0700
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-27 12:03 -0700
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-27 12:11 -0700
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-27 15:53 -0700
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-26 17:59 -0400
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-26 22:18 +0000
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-26 18:33 -0400
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-26 17:22 -0700
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-27 00:03 -0700
Re: C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-27 14:13 -0400
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-27 12:15 -0700
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-29 09:43 -0700
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-29 11:59 -0700
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-07-01 18:32 -0700
Re: C scope and struct definitions pacman@kosh.dhis.org (Alan Curry) - 2012-06-27 20:59 +0000
Re: C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-28 16:42 -0400
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-23 20:57 -0400
Re: C scope and struct definitions Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-23 22:11 -0400
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-23 22:51 -0400
Re: C scope and struct definitions Nick Bowler <nbowler@draconx.ca> - 2012-06-25 17:31 +0000
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-25 14:46 -0400
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-25 14:43 -0700
Re: C scope and struct definitions Jens Gustedt <jens.gustedt@loria.fr> - 2012-06-26 13:44 +0200
Re: C scope and struct definitions Keith Thompson <kst-u@mib.org> - 2012-06-23 20:07 -0700
Re: C scope and struct definitions Jens Gustedt <jens.gustedt@loria.fr> - 2012-06-24 10:56 +0200
Re: C scope and struct definitions James Kuyper <jameskuyper@verizon.net> - 2012-06-24 08:29 -0400
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-24 10:26 -0700
Re: C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-25 10:50 -0400
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-24 09:23 -0700
Re: C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-25 11:17 -0400
Re: C scope and struct definitions Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-25 14:22 -0700
Re: C scope and struct definitions Kenneth Brody <kenbrody@spamcop.net> - 2012-06-25 11:11 -0400
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