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| From | Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> |
|---|---|
| Newsgroups | comp.arch, comp.lang.c |
| Subject | Re: Non-constant initializers |
| Date | 2011-05-12 23:28 +0000 |
| Organization | Bottomfeeder Technical Consulting spa |
| Message-ID | <i1u9RB.8qd.j2hEc@btdt.invalid> (permalink) |
| References | (2 earlier) <iqgjdo$ggt$1@gosset.csi.cam.ac.uk> <0ca8ca5b-e73e-418a-935f-0fcc17fdf404@q14g2000prh.googlegroups.com> <iqgp2j$h9h$1@gosset.csi.cam.ac.uk> <OgcdY5.Lcq.Cst0A@btdt.invalid> <chine.bleu-C88A78.16153612052011@reserved-multicast-range-not-delegated.example.com> |
Cross-posted to 2 groups.
On Thu, May 12, 2011 at 04:15:36PM -0700, Columbus sailed the ocean China Blue wrote:
> In article <OgcdY5.Lcq.Cst0A@btdt.invalid>,
> Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> wrote:
>
> > Hey guys,
> >
> > I've been writing some code that I would prefer to be maximally
> > portable. As I have mostly used Linux, gcc is pretty much the only C
> > compiler I've ever used under UN*X. I'd like to use non-constant
> > initializers for some global variables. I'm pretty sure I can get it
> > to work the way I want under gcc, but what of other compilers? The
> > gcc documentation in info format says that ISO C99 allows this, and so
> > I expect some compilers built in the 90's will support the feature,
> > but to what extent is this true?
> >
> > What I mean to learn is the general prevalence of this C feature. If
> > there's no support for certain well-known platforms (maybe SunOS or
> > OSF/1, whatever) I may consider a different solution to the original
> > problem, but I'd like to know what I'm getting in to before I start
> > trying to read the docs for every bloody C compiler that ever hit the
> > 'net in the last twenty years.
>
> I use an alternative strategy: if I want to implement
> static double XYZ = nonconstant-expression;
>
> I instead do
> #define XYZ (*XYZ_())
> static double *XYZ_(void) {
> static double xyz;
> static bool initialised = false;
> LOCK
> if (!initialised) {
> xyz = nonconstant-expression;
> initialised = true;
> }
> UNLOCK
> return &xyz;
> }
>
> XYZ will be an lvalue just like any other variable; it gets initialised on the
> first use; the initialisation can be any complicated as desired, using any
> dependencies desired, without depending on the compiler and loader to sneak in
> the initialisation code in the right order.
Hey, is that how you ancients did things in the 80's era? I hope
there's a better way.
Fred the Freshwater Catfish
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Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-12 22:59 +0000
Re: Non-constant initializers Ian Collins <ian-news@hotmail.com> - 2011-05-13 11:07 +1200
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-12 23:17 +0000
Re: Non-constant initializers Ian Collins <ian-news@hotmail.com> - 2011-05-13 11:20 +1200
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-12 23:30 +0000
Re: Non-constant initializers Ian Collins <ian-news@hotmail.com> - 2011-05-13 11:34 +1200
Re: Non-constant initializers Keith Thompson <kst-u@mib.org> - 2011-05-12 16:52 -0700
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-14 00:13 +0000
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-14 01:28 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 13:52 -0400
Re: Non-constant initializers kym@kymhorsell.com - 2011-05-14 01:54 +0000
Re: Non-constant initializers Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-14 01:07 -0700
Re: Non-constant initializers kym@kymhorsell.com - 2011-05-14 09:22 +0000
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-14 17:14 +0000
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-14 00:11 +0000
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-12 18:08 -0500
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-12 19:22 -0400
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-12 18:53 -0500
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 13:59 -0400
Re: Non-constant initializers Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-14 14:19 -0400
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-14 15:04 -0500
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 15:10 -0400
Re: Non-constant initializers James Kuyper <jameskuyper@verizon.net> - 2011-05-14 16:01 -0400
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 16:57 -0400
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-14 14:30 -0500
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 15:25 -0400
Re: Non-constant initializers Keith Thompson <kst-u@mib.org> - 2011-05-14 13:05 -0700
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 17:00 -0400
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-14 16:14 -0500
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-14 16:49 -0500
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 18:21 -0400
Re: Non-constant initializers Shao Miller <sha0.miller@gmail.com> - 2011-05-14 21:26 -0500
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-15 14:01 -0400
Re: Non-constant initializers Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-14 17:45 -0400
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-14 18:09 -0400
Re: Non-constant initializers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-05-15 04:01 +0100
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-15 13:26 -0400
Re: Non-constant initializers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-05-16 02:32 +0100
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-15 03:59 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-16 04:49 -0400
Re: Non-constant initializers pete <pfiland@mindspring.com> - 2011-05-16 07:27 -0400
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-16 09:24 -0400
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-16 19:10 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-16 21:23 -0400
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-16 19:10 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-16 21:16 -0400
Re: Non-constant initializers James Kuyper <jameskuyper@verizon.net> - 2011-05-16 21:37 -0400
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-16 22:42 -0400
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-17 02:40 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-16 22:50 -0400
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-17 04:14 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-17 17:37 -0400
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-17 22:22 +0000
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-17 18:33 -0400
Re: Non-constant initializers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-05-18 01:58 -0700
Re: Non-constant initializers Uncle Steve <stevet810@gmail.com> - 2011-05-18 12:45 -0400
Re: Non-constant initializers "io_x" <a@b.c.invalid> - 2011-05-18 19:30 +0200
Re: Non-constant initializers Dr Nick <3-nospam@temporary-address.org.uk> - 2011-05-18 20:01 +0100
Re: bug-free C code (was: Non-constant initializers) Seebs <usenet-nospam@seebs.net> - 2011-05-19 02:21 +0000
Re: bug-free C code (was: Non-constant initializers) Keith Thompson <kst-u@mib.org> - 2011-05-18 20:00 -0700
Re: bug-free C code (was: Non-constant initializers) Seebs <usenet-nospam@seebs.net> - 2011-05-19 03:14 +0000
Re: bug-free C code (was: Non-constant initializers) Keith Thompson <kst-u@mib.org> - 2011-05-19 07:49 -0700
Re: bug-free C code (was: Non-constant initializers) Seebs <usenet-nospam@seebs.net> - 2011-05-19 15:16 +0000
Re: bug-free C code Ben Pfaff <blp@cs.stanford.edu> - 2011-05-18 20:02 -0700
Re: bug-free C code Keith Thompson <kst-u@mib.org> - 2011-05-18 20:09 -0700
Re: bug-free C code Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-18 23:24 -0400
Re: bug-free C code Angel <angel+news@spamcop.net> - 2011-05-19 06:39 +0000
Re: bug-free C code Keith Thompson <kst-u@mib.org> - 2011-05-19 08:05 -0700
Re: bug-free C code Angel <angel+news@spamcop.net> - 2011-05-19 16:22 +0000
Re: bug-free C code Keith Thompson <kst-u@mib.org> - 2011-05-19 11:36 -0700
Re: bug-free C code Ben Pfaff <blp@cs.stanford.edu> - 2011-05-19 12:21 -0700
Re: bug-free C code Keith Thompson <kst-u@mib.org> - 2011-05-19 13:12 -0700
Re: bug-free C code gazelle@shell.xmission.com (Kenny McCormack) - 2011-05-19 21:52 +0000
Re: bug-free C code Angel <angel+news@spamcop.net> - 2011-05-19 22:16 +0000
Re: bug-free C code Shao Miller <sha0.miller@gmail.com> - 2011-05-19 17:25 -0500
Re: bug-free C code Kenneth Brody <kenbrody@spamcop.net> - 2011-05-20 13:32 -0400
Re: bug-free C code gazelle@shell.xmission.com (Kenny McCormack) - 2011-05-19 21:51 +0000
Re: bug-free C code Kenneth Brody <kenbrody@spamcop.net> - 2011-05-20 13:30 -0400
Re: bug-free C code "Joel C. Salomon" <joelcsalomon@gmail.com> - 2011-05-18 23:13 -0400
Re: bug-free C code Dr Nick <3-nospam@temporary-address.org.uk> - 2011-05-19 08:23 +0100
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-13 00:15 +0000
Re: Non-constant initializers "io_x" <a@b.c.invalid> - 2011-05-13 11:01 +0200
Re: Non-constant initializers Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-12 16:30 -0700
Re: Non-constant initializers Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-12 16:15 -0700
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-12 23:28 +0000
Re: Non-constant initializers Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-05-12 18:01 -0600
Re: Non-constant initializers Keith Thompson <kst-u@mib.org> - 2011-05-12 18:15 -0700
Re: Non-constant initializers Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-05-12 22:56 -0600
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-13 05:18 +0000
Re: Non-constant initializers Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-05-13 09:10 -0600
Re: Non-constant initializers Seebs <usenet-nospam@seebs.net> - 2011-05-13 20:56 +0000
Re: Non-constant initializers Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-18 23:47 -0700
Re: Non-constant initializers Keith Thompson <kst-u@mib.org> - 2011-05-19 08:15 -0700
Re: Non-constant initializers Fred the Freshwater Catfish <usenet.fred@bdtd.invalid> - 2011-05-13 23:57 +0000
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