/dev/chat

3:23 PM

@FaheemMitha Nope, haven't seen the answer to your Chromium question

And over 1000 messages in the chat log... You all have been busy!

@derobert Ooh, super-belated answer. Good weekend?

Yep. Had fun at Otakon

@derobert the funny thing is, you should have known the answer. See my comments in the question.

@derobert Oakton? That sounds like a place that should be in California.

@FaheemMitha Wow, LOL, that was a while ago!

@derobert No kidding.

3:28 PM

I'm surprised your system was set to an en_US locale...

Though, apparently actually in Virginia.

Maryland, actually

otakon.com or en.wikipedia.org/wiki/Otakon

@derobert I used to live there. Partly, force of habit. Partly, I had somehow got the impression that if you are using a USA style keyboard you need to use a USA locale. This is probably wrong, when I think about it.

@derobert Oh, I thought you had terrible-typed Oakton, and searched for that.

Ah, anime.

Wouldn't have you pegged for an anime fan, somehow. Isn't that supposed to be for teenage girls?

@derobert any idea what internal rules Chromium follows? Does it just look at LC_PAPER?

@FaheemMitha Some of them are. There's a fairly wide variety. Though most of it is for people younger than me.

@FaheemMitha no idea...

Always wonder what people do at conventions. Dress up in silly costumes and have sword fights?

@derobert Ok.

@derobert Ok. I meant to grep the Chromium sources for LC_PAPER. I guess I can do that now.

3:32 PM

@FaheemMitha Costumes, yes, definitely. Not many sword fights though. Probably none beyond putting two fake swords next to each other for a photo.

@derobert Ah. So, costumes and what else? Skits?

@FaheemMitha Yeah, there are some of those. Also panels (some education, some just entertaining). A lot of meeting with friends, too.

I suppose with costumes come best costume contests.

@derobert Sounds good. Social scene, then?

@FaheemMitha yes, there are those. I didn't go to the one at Otakon. Conflicted with the anime music video contest

@derobert Wow, music video. Samples?

3:35 PM

I'd like to show you the best one there... but haven't found a copy on line yet. So, I'll find something else... Any anime you've seen?

@derobert Can't think of anything off the top of my head. I must have, I guess.

So, do you concur with adding LC_PAPER="en_BR.UTF8" in /etc/default/locale, per Gilles?

if that works, sounds fine.

@derobert I haven't tried it yet.

Is that terrible Pokeman thing anime? And no, don't want a video of that.

Ah, there is that Japanese guy who did that film of Howls Moving Castle etc.

That's probably anime.

Huh, no matches for LC_PAPER. Odd.

@FaheemMitha Yes, that's anime. Have you seen Totoro (same guy, Miyazaki, who did Howl's Moving Castle)?

@derobert No.

I've seen Howl... because I'm kind of a DWJ fan. Though it really didn't have much to do with the book. I think I might have seen another one. About a princess, and some vengeance involving the forces of nature.

Monoake?

3:51 PM

Yes, Princess Mononoke

Or maybe thought I saw it. Certainly been a long time.

Howls Moving Castle would seem a bit weird if there was a faithful translation to screen in that style. It's so English.

Sounds like an amine version of Avatar.

@derobert How is it?

animemusicvideos.org/members/members_videoinfo.php?v=1838 ... there is one that's good and has Princess Mononoke in it. Couldn't find a copy on YouTube (and you need an account to download or stream it from that site). Account is free, however. Or there is a copy at amv.celestravideo.com/2001amv.html that you'd have to download

@derobert Great. Thanks for looking.

When we send a packet from a sending host, the packet is created. After this, the computer looks at the packet destination address and compares it to the routing table that it has. If the destination address is local, the packet is sent directly to that address via its hardware MAC address.

Where will this configuration file be? In other words, where is this routing table located?

@FaheemMitha or here is one from a different show (you probably haven't seen), which is a different style of video. More or less making fun of all the product placement in the show youtube.com/watch?v=pzMctd8bb20

4:02 PM

@derobert ok. I'll watch this.

Well, I got through aboout half of it.

@Ramesh Isn't this what iptables handles?

@FaheemMitha yeah. I am learning the concepts of IPTables.

i.e. netfilter

Netfilter

Netfilter is a framework inside the Linux kernel which offers flexibility for various networking-related operations to be implemented in form of customized handlers. Netfilter offers various options for packet filtering, network address translation, and port translation. These functions provide the functionality required for directing packets through a network, as well as for providing ability to prohibit packets from reaching sensitive locations within a computer network. Netfilter represents a set of hooks inside the Linux kernel, thus it allows specific kernel modules to register callbac...

@FaheemMitha Memories Dance is a serious video (unlike that one on YouTube)

@FaheemMitha, do you mean this is the firewall configuration? That is, /etc/sysconfig/iptables ?

@Ramesh Maybe, not sure. I think there are different ways to hook into the kernel.

People who actually use this stuff would know.

4:07 PM

@FaheemMitha Do netfilter and iptables refer to the same?

I see this entry from History of wiki entry.

@Ramesh iptables is a userspace program. netfilter is a kernel thing

Rusty Russell started the netfilter/iptables project in 1998

the former manipulates the latter. read the netfilter wp article.

@FaheemMitha, thanks. So, the iptables more or less work on application layer and the netfilter works on IP layer, is it?

@Ramesh what is IP layer? And I don't really know enough about it, sorry.

There are probably networking people around who could give you a detailed explanation.

4:10 PM

@FaheemMitha, ok. I was referring to the 7 layers of OSI model.

@Ramesh OSI?

And I am also still naive to these concepts :)

OSI model

The Open Systems Interconnection model (OSI) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers. The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO), maintained by the identification ISO/IEC 7498-1. The model groups communication functions into seven logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the...

@Ramesh ok

@Ramesh You mean uninformed, not naive, I think.

@FaheemMitha oh, what is naive?

Naive has more connotations like innocence.

Like a child.

4:12 PM

@Ramesh netfilter works on layers 5 and below (on the OSI model). Maybe there is some layer 6 stuff in there, not entirely sure.

See dictionary definitions. If you don't want language corrections, please say so. Some people don't like it.

@FaheemMitha nothing like that :) You can correct something if am wrong. I do not mind.

@Ramesh Indians frequently speak and write terrible English, but are entirely uninterested in being corrected (in the main).

@derobert Thanks. So is there any conceptual difference between iptables and netfilter?

@FaheemMitha unfortunately it's true. :(

@Ramesh I thought I covered that. :-)

4:15 PM

@Ramesh Strictly speaking, iptables is the config & management tool, netfilter is the code running in the kernel. But people will often call the whole thing iptables.

@derobert And there seem to be some alternative systems on the horizon. It's confusing.

Also, its in the process of being replaced by nftables

e.g. nftables

@derobert thanks.

Which seems to be one name for both the userspace and kernel things

4:18 PM

@FaheemMitha yeah, from the wiki page, nftables is a combination of a Linux kernel engine, and a userspace utility.

@derobert do you do much networking stuff?

@FaheemMitha Well, nft is the new userland tool

@FaheemMitha Yeah. Do a fair bit. Nothing extremely complicated though.

@derobert oh. are people using it now. and is it one or the other? what if you try to use both?

Not sure what happens if you try to use both, or how much use nftables is actually in.

nftables is also part of the Netfilter project...

I think the goal is to get the iptables command-line tools to talk to the nftables kernel side. So then you could use both at once, at least somewhat.

@derobert what is the purpose of it?

4:21 PM

netfilter.org/projects/nftables/index.html explains

basically, I think its to eliminate a lot of redundant kernel code

Also, is there any mapping for existing IPv4 addresses to IPv6?

@FaheemMitha Probably in GTK

gtk/gtkpapersize.c

const gchar *
gtk_paper_size_get_default (void)
{
  char *locale, *freeme = NULL;
  const char *paper_size;

#if defined(HAVE__NL_PAPER_HEIGHT) && defined(HAVE__NL_PAPER_WIDTH)
  {
    int width = NL_PAPER_GET (_NL_PAPER_WIDTH);
    int height = NL_PAPER_GET (_NL_PAPER_HEIGHT);

    if (width == 210 && height == 297)
      return GTK_PAPER_NAME_A4;

    if (width == 216 && height == 279)
      return GTK_PAPER_NAME_LETTER;
  }
#endif

#ifdef G_OS_WIN32
  freeme = locale = g_win32_getlocale ();
#elif defined(LC_PAPER)

@derobert Wow, impressive detective work. You should add an answer.

Else, it will be lost in the barren wastelands of the chat archive.

4:42 PM

@FaheemMitha Added one

@derobert "Next, on systems with LC_PAPER, it'll get that locale setting. Otherwise, it'll use the LC_MESSAGES locale setting. Linux/glibc has LC_PAPER". How do these differe,a nd what can you set them to? Oh, and is the former an env variable?

They're both environment variables, or can be

@derobert Oh, and so how do they differ? Does the latter live in a special namespace or something?

@FaheemMitha LC_PAPER is just for changing your paper locale (basically paper size). LC_MESSAGES is for messages displayed on screen

Aug 9 at 12:20, by Faheem Mitha

@damien Sure thing. Don't start thinking you are responsible for the people who happen to wander in here, of course. That way lies madness.

Apparently, close to Shakespeare quote. Live and learn

enotes.com/shakespeare-quotes/that-way-madness-lies

@derobert Ok, I misread. Let me look again.

@derobert Ok, this question was based on a misreading. I thought I saw LC_PAPER twice.

@derobert "Finally, it uses a hardcoded list of locales that use US Letter". You referred to locales earlier. Are you talking about the LANG setting?

4:54 PM

LC_PAPER="en_US.UTF-8" ... that thing

I should say country codes there

@derobert I'm talking your option 4. If LC_PAPER is unset, etc.

"list of locales that use US Letter" means what, exactly?

try now...

"compares the locale". stlll fuzzy what a locale is. time to read the WP article again.

"a locale is a set of parameters".

So, "it compares the locale against a hardcoded list of country codes" means what, exactly? Sorry, ex-mathematician here.

setlocale returns a string along the lines of en_US.UTF-8

it compares that against a list of country codes

tried again...

Gilles' locale answer is actually somewhat better than the WP article. I wonder if Gilles edits WP.

@derobert hmm, setlocale?

I think this might be the LANG variable.

"A successful call to setlocale() returns an opaque string that corresponds to the locale set." <- man setlocale

"The argument locale is a pointer to a character string containing the required setting of category."

5:01 PM

@FaheemMitha Odd, you're right, that is what the manpage says

So locale is used here to be a character setting, or category. Both of these cannot be right.

I smell terminology abuse. We math people hate that stuff.

Ok. Need to go look at the gtk2 source again...

Or should that be abuse of definition?

the GTK2 source is definitely not treating it like an opaque string

"Upon successful completion, setlocale() shall return the string associated with the specified category for the new locale. Otherwise, setlocale() shall return a null pointer and the global locale shall not be changed." That's what the Single Unix Spec says.

@derobert That actually sounds more sensible.

"string associated with the specified category for the new locale." I can live with.

If you replace "Otherwise, it compares the locale" with "compares the string associated with the specified category for the locale" that would read better.

In any case, the intent seems to be for this string to act as a global identifier for a set of parameters.

@derobert What is an opaque string?

I wonder if I can be bothered to argue with the manpage authors about their defn.

5:10 PM

Something you're not supposed to assume anything about. That's what it means to be opaque. You can pass it back to library functions, but not do anything else with it.

Anyway, I removed that bit, as its probably just a mistake in the manpage.

@derobert Ok.

An example of a non-opaque string is when you can assume something about its structure?

Yes. So if you say it returns language code, underscore, country code, etc., that's non-opaque. You are free to parse it to extract the country code from it.

If you say its opaque, that means you're not allowed to do that. The library authors aren't making any promise not to change it to something else in the future, and not consider that an ABI change.

I'm confused about your usage of "locale setting" and "locale string". Is "locale setting" what a particular parameter within the locale set is, er, set to? And the locale string is a global identifier?

"Next, on systems with LC_PAPER, it'll get that locale setting." I'm a bit fuzzy what that means. Since LC_PAPER may take the default "locale string" or can override it with its own setting.

There seems to be an unfortunate tendency to conflate "a set of parameters" with a string. I think a locale is the former, not the latter. A string identifies a particular locale category.

Eg en_US en_BR etc.

Hmmm...

@FaheemMitha Ok, another try!

5:27 PM

@derobert Don't feel compelled to humor my OCD. It doesn't actually matter that much, and you are not writing a research paper. FYI, if you were writing a research paper, you would get a lot of this stuff from the reviewers.

Academic reviewers can be extremely... annoying.

It seems each parameter in a locale can be associated with a separate locale category, with no restrictions. I wonder what it does, it it cannot identify the category. Suppose I set LC_PAPER to "foo", for example.

@derobert Better.

@FaheemMitha it'd either fall back to LANG or alternatively get no locale. If it got no locale, it'd assume A4.

(I'm not sure which)

@derobert Hmm. Complicated.

@derobert you forgot to quote that code. I would.

It's long and not under a compatible license with the SE post. So I didn't bother.

I bet I can find it to link to, though

"LC_PAPER category" probably should be "LC_PAPER parameter".

Nah, they call them categories. That's the language the spec used.

5:33 PM

The relevant category in this context is the country thing - en_US.UFT8 etc.

@derobert Oh, really. And the other category is global label for the spec?

I think that is an unfortunate overuse of the word.

"a string associated with the specified category for the locale" ... category in that means, e.g., LC_PAPER or LC_MESSAGES

@derobert If that is what it means, I've misread it. Where is this from again?

Oh right, the setlocale man page

@FaheemMitha pubs.opengroup.org/onlinepubs/9699919799/functions/…

I see, it seems "category" can designate the global locale, or only a part thereof. E.g. one parameter like LC_PAPER.

As defined by the API.

"Setting all of the categories of the global locale is similar to successively setting each individual category of the global locale". Yes, looks like you are right there.

It seems on cannot actually set LC_PAPER to say "a4", which would really be simpled

5:48 PM

Yeah. Too bad, it'd be much more useful that way.

Apparently /etc/default/locale is not a standard. Bummer.

Nope, it's a Debian thing.

@derobert Did you see Gilles locale answer? It's quite good. Better than the WP article.

@derobert So I just discovered.

@FaheemMitha Not sure if I've seen it.

A: What should I set my locale to and what are the implications of doing so?

6

Locale settings are user preferences that relate to your culture. Locale names On all current unix variants that I know of (but not on a few antiques), locale names follow the same pattern: An ISO 639-1 lowercase two-letter language code, or an ISO 639-2 three-letter language code if the lan...

@derobert you agree with him about unsetting LC_COLLATE and LC_NUMERIC? I guess I have it set, like most everyone.

5:56 PM

I donno. I like LC_COLLATE set. Gives sane sorting in ls, for example.

LC_NUMERIC doesn't matter (to me) because en_US format is the default

@derobert Ok.

@derobert Oh. I think I'll just leave them alone - it looks pretty marginal.

@derobert you didn't add the code link?

not yet, got distracted posting a btrfs question

6:12 PM

@derobert ok

If you are in the market for a web comic, check out Cheshire Crossing. Good stuff. And short too. Just 4 issues.

@FaheemMitha link added

Today is apparently just a day for reading source code... unix.stackexchange.com/questions/149932/…

@derobert You could send a patch. Or a bug report.

Yes. A patch would be a nice thing, to fix the manpage.