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| From | jt@toerring.de (Jens Thoms Toerring) |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: initialization of local static variable |
| Date | 2011-10-07 11:11 +0000 |
| Organization | Freie Universitaet Berlin |
| Message-ID | <9f852eF700U1@mid.uni-berlin.de> (permalink) |
| References | <16f1e150-05c8-4e30-a0e3-17aa3182f14d@d28g2000vby.googlegroups.com> <chine.bleu-1373B4.03030507102011@news.eternal-september.org> <j6mkhb$m4s$1@dont-email.me> |
BartC <bc@freeuk.com> wrote:
> "China Blue Corn Chips" <chine.bleu@yahoo.com> wrote in message
> news:chine.bleu-1373B4.03030507102011@news.eternal-september.org...
> > In article
> > <16f1e150-05c8-4e30-a0e3-17aa3182f14d@d28g2000vby.googlegroups.com>,
> > "V.Subramanian, India" <subramanian100in@yahoo.com> wrote:
> >
> >> consider the following program x.c:
> >> #include <stdlib.h>
> >> #include <stdio.h>
> >>
> >> char first[] = "test message";
> >
> > The address of first is known when the program is loaded.
> The address of first, yes; it's contents are initially set to point to "test
> message".
I guess that you overlooked that 'first' isn't a pointer but
an array (which would explain most of what you wrote in the
following). Thus memory for it is made available and initia-
lized (to "test message") when the program is loaded. Its
address is, of course, known at that point in time.
> >> void display(void)
> >> {
> >> static char* p_first = first + 5;
> >
> > p_first is initialised when the program is loaded with address already
> > known.
> But 'first' refers to it's contents, not it's address.
'first + 5' evaluates to the address of (the first element of)
'first, incremented by 5 - there's nothing refering to the con-
tent of 'first'. Since 'first is an array (not a pointer) we've
got the common conversion of an array to a pointer to its first
element when the array is used where a value is required.
> The contents might
> have changed (point to another string) by the time display() gets called.
The content of the array 'first' could have changed, yes, but it
will still have the same address.
> (I'm assuming p_first is re-initialised on each entry to the function.)
No, 'p_first', being a static variable, is initialized exactly
once when the program is loaded - at least that's how I would
tend to interpret 3.1.2.4 in C89:
An object declared with external or internal linkage, or with the
storage-class specifier static has static storage duration. For such
an object, storage is reserved and its stored value is initialized
only once, prior to program startup.
Regards, Jens
--
\ Jens Thoms Toerring ___ jt@toerring.de
\__________________________ http://toerring.de
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initialization of local static variable "V.Subramanian, India" <subramanian100in@yahoo.com> - 2011-10-06 23:33 -0700
Re: initialization of local static variable pete <pfiland@mindspring.com> - 2011-10-07 02:51 -0400
Re: initialization of local static variable "BartC" <bc@freeuk.com> - 2011-10-07 10:44 +0100
Re: initialization of local static variable China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-10-07 03:03 -0700
Re: initialization of local static variable "BartC" <bc@freeuk.com> - 2011-10-07 11:33 +0100
Re: initialization of local static variable jt@toerring.de (Jens Thoms Toerring) - 2011-10-07 11:11 +0000
Re: initialization of local static variable "BartC" <bc@freeuk.com> - 2011-10-07 12:51 +0100
Re: initialization of local static variable jt@toerring.de (Jens Thoms Toerring) - 2011-10-07 15:56 +0000
Re: initialization of local static variable Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-07 20:29 +0100
Re: initialization of local static variable jacob navia <jacob@spamsink.net> - 2011-10-07 21:38 +0200
Re: initialization of local static variable Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-07 21:16 +0100
Re: initialization of local static variable jacob navia <jacob@spamsink.net> - 2011-10-07 22:22 +0200
Re: initialization of local static variable jt@toerring.de (Jens Thoms Toerring) - 2011-10-07 22:25 +0000
Re: initialization of local static variable jacob navia <jacob@spamsink.net> - 2011-10-08 00:40 +0200
Re: initialization of local static variable Ian Collins <ian-news@hotmail.com> - 2011-10-08 11:56 +1300
Re: initialization of local static variable jacob navia <jacob@spamsink.net> - 2011-10-08 01:53 +0200
Re: initialization of local static variable Jens Gustedt <jens.gustedt@loria.fr> - 2011-10-09 23:04 +0200
Re: initialization of local static variable Andrew Haley <andrew29@littlepinkcloud.invalid> - 2011-10-10 11:54 -0500
Re: initialization of local static variable Ike Naar <ike@sverige.freeshell.org> - 2011-10-10 17:41 +0000
Re: initialization of local static variable Andrew Haley <andrew29@littlepinkcloud.invalid> - 2011-10-10 17:35 -0500
Re: initialization of local static variable jt@toerring.de (Jens Thoms Toerring) - 2011-10-08 00:02 +0000
Re: initialization of local static variable "BartC" <bc@freeuk.com> - 2011-10-08 01:26 +0100
Re: initialization of local static variable "Philip Lantz" <prl@canterey.us> - 2011-10-08 03:01 -0700
Re: initialization of local static variable "BartC" <bc@freeuk.com> - 2011-10-07 21:42 +0100
Re: initialization of local static variable China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-10-07 16:25 -0700
Re: initialization of local static variable jacob navia <jacob@spamsink.net> - 2011-10-08 01:51 +0200
Re: initialization of local static variable China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-10-07 18:21 -0700
Re: initialization of local static variable Nobody <nobody@nowhere.com> - 2011-10-08 15:36 +0100
Re: initialization of local static variable Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-08 22:06 +0100
Re: initialization of local static variable Nobody <nobody@nowhere.com> - 2011-10-09 05:35 +0100
Re: initialization of local static variable Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-09 09:25 +0100
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-09 11:00 +0200
Re: initialization of local static variable Barry Schwarz <schwarzb@dqel.com> - 2011-10-09 10:56 -0700
Re: initialization of local static variable James Kuyper <jameskuyper@verizon.net> - 2011-10-09 14:30 -0400
Re: initialization of local static variable Barry Schwarz <schwarzb@dqel.com> - 2011-10-09 21:43 -0700
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-10 19:08 +0200
Re: initialization of local static variable Geoff <geoff@invalid.invalid> - 2011-10-10 16:16 -0700
Re: initialization of local static variable Ike Naar <ike@iceland.freeshell.org> - 2011-10-10 23:22 +0000
Re: initialization of local static variable James Kuyper <jameskuyper@verizon.net> - 2011-10-10 20:40 -0400
Re: initialization of local static variable Barry Schwarz <schwarzb@dqel.com> - 2011-10-10 20:54 -0700
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-11 18:45 +0200
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-11 18:51 +0200
Re: initialization of local static variable Barry Schwarz <schwarzb@dqel.com> - 2011-10-11 18:52 -0700
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-12 08:49 +0200
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-11 19:48 +0200
Re: initialization of local static variable Barry Schwarz <schwarzb@dqel.com> - 2011-10-11 21:25 -0700
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-12 08:48 +0200
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-12 08:54 +0200
Re: initialization of local static variable pete <pfiland@mindspring.com> - 2011-10-12 20:55 -0400
Re: initialization of local static variable Barry Schwarz <schwarzb@dqel.com> - 2011-10-11 18:52 -0700
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-11 19:55 +0200
Re: initialization of local static variable Keith Thompson <kst-u@mib.org> - 2011-10-11 11:24 -0700
Re: initialization of local static variable Keith Thompson <kst-u@mib.org> - 2011-10-11 12:47 -0700
Re: initialization of local static variable "io_x" <a@b.c.invalid> - 2011-10-12 08:49 +0200
Re: initialization of local static variable Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 16:09 -0800
Re: initialization of local static variable China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-10-07 16:06 -0700
Re: initialization of local static variable Seebs <usenet-nospam@seebs.net> - 2011-10-12 22:25 +0000
Re: initialization of local static variable "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2011-10-13 07:09 -0700
Re: initialization of local static variable Seebs <usenet-nospam@seebs.net> - 2011-10-17 17:21 +0000
Re: initialization of local static variable Joe Wright <joewwright@comcast.net> - 2011-10-14 14:27 -0400
Re: initialization of local static variable Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-08 00:03 -0400
Re: initialization of local static variable China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-10-08 01:27 -0700
Re: initialization of local static variable Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-08 00:08 -0400
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