Are PHP libraries linked dynamically or statically?

[Martin Larsen]

Hi,

When a PHP program links to a library using include or require (or their
_once variations), is the library then linked dynamically or statically?

While it might seem irrelevant from a technical point of view, the
linking method is important when it comes to licencing issues as some
licences, like GPL, differ between those kinds of linking when it comes
to viewing the library as a derivative work of the main program.

Therefore it is quite important to know what kind of linking is in
effect when including libraries, and I hope someone in this group can
shed some light on this matter.

Thank you very much in advance,
Martin

[Rami Elomaa]

Martin Larsen kirjoitti:

Hi Henk,

>This may be true from a strict technical definition, but juridical
reasoning may not be that strict.

Thank you for making clear what I was trying to say. It is in fact a
juridical matter.

If we agree that the term linking might not be entirely irrelevant,
which kind of linking would you say is in effect when a PHP program
links to a script: dynamically or statically.

The reason why this is important is that dynamically linking is often
seen as a licence boundary
(http://en.wikipedia.org/wiki/Library...ynamic_linking)

Looking at this definition:

"Dynamic linking means that the subroutines of a library are loaded into
an application program at runtime, rather than being linked in at
compile time, and remain as separate files on disk."

Based on that I'd say php "linking" resembles more dynamic linking than
static linking, since there is no separate "compile time" per se, a
script is each time recompiled at runtime. Plus the included scripts are
separate files on disk, they are not "built" into one executable.

And the reason I say it _resembles more_ is the basic problem that
neither of these terms can really be applied to php scripts, what you
need is a new term: call it including.

--
Ra*********@gma il.com

"Wikipedia on vähän niinq internetin raamattu, kukaan ei pohjimmiltaan
usko siihen ja kukaan ei tiedä mikä pitää paikkansa." -- z00ze

[Andy Hassall]

On Fri, 20 Jul 2007 01:14:02 +0200, Martin Larsen
<ma************ ********@bigfoo t.comwrote:

>When a PHP program links to a library using include or require (or their
_once variations), is the library then linked dynamically or statically?

While it might seem irrelevant from a technical point of view, the
linking method is important when it comes to licencing issues as some
licences, like GPL, differ between those kinds of linking when it comes
to viewing the library as a derivative work of the main program.

Therefore it is quite important to know what kind of linking is in
effect when including libraries, and I hope someone in this group can
shed some light on this matter.

Have you seen the following - not sure if it helps, or muddies the waters
further:

http://www.gnu.org/licenses/gpl-faq....terpreterIsGPL

In particular the final two paragraphs:

"Another similar and very common case is to provide libraries with the
interpreter which are themselves interpreted. For instance, Perl comes with
many Perl modules, and a Java implementation comes with many Java classes.
These libraries and the programs that call them are always dynamically linked
together.

A consequence is that if you choose to use GPL'd Perl modules or Java classes
in your program, you must release the program in a GPL-compatible way,
regardless of the license used in the Perl or Java interpreter that the
combined Perl or Java program will run on. "
The implication appears to be that loading Perl modules is treated as "dynamic
linking" for the purposes of the license (pure technical definitions aside).
Perl modules are often "pure-Perl" and so very closely match "require/include"
for PHP libraries.

--
Andy Hassall :: an**@andyh.co.u k :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Toby A Inkster]

Jerry Stuckle wrote:

Ah, but OpenOffice is not MS Word. And just because OpenOffice
implements something one way doesn't mean Word does.

No, no -- the quotes from the OpenOffice.org developers were regarding
the MS Word ".doc" file format -- which they had to reverse engineer --
they were not on the subject of OpenOffice.org' s behaviour.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.12-12mdksmp, up 32 days, 4:23.]

Parsing an HTML Table with PEAR's XML_HTTPSax3
http://tobyinkster.co.uk/blog/2007/0...table-parsing/

[Martin Larsen]

Jerry Stuckle wrote:

Martin Larsen wrote:

>Is there a way to contact the PHP Group directly?

Why?

If you understood the technology, the answer would be clear. Rather, I
suggest you visit your local library or bookstore and find out how
interpreters work.

Ok, I will tell you why. I had hoped it was not necessary, but here it is...

I do in fact know how interpreters work. I have actually written one
myself. Being a professional windows programmer for ages, I have also
learned the hard way the distinct difference between dynamic and static
libraries: missing DLL files on the end user's computer preventing the
programs from even starting.

I deliberately asked the question in a simple minded manner as I did not
want my own view of the matter to bias the replies. The thing is that
the core team behind a major CMS (Joomla) has recently changed their
mind about non-GPL plugins (or scripts, if you like). Until then they
accepted and welcomed proprietary plugins, but now they say that since
the CMS is GPL, the plugins must also be GPL to comply.

Now, I don't wish this thread to be for or against GPL. I only want to
discuss the reasoning behind their claims. The point is that they argue
that most extensions are *derivative work* of the CMS (even though they
normally don't include a single line of code from it) because they are
statically linked to the CMS. If they were dynamically linked, the
matter would be different.

Yep, that is what they say. While you and I can agree that it doesn't
make much sense to talk about linking for interpreters, they
nevertheless use it in their argumentation. And that is why I asked the
question: Are PHP libraries linked dynamically or statically?

In my opinion they make two mistakes: the first is to talk about linking
at all, the second is to claim that the plugins are statically linked.

As I see it, even when we are not really talking linking, the
characteristics of the processes involved in the INCLUDE more closely
resembles dynamic linking than static linking. Which means that their
argumentation is wrong no matter what.

As it happens, we (third-party developers for Joomla) have tried hard to
make them see that their arguments are wrong. But they keep claiming
that the scripts are statically linked and thus derivative works of the CMS.

And now to my question: Is there a way to contact the PHP Group directly?

I have an idea that if we could get a "official" statement of the
linking or non-linking involved, they might be more prone to listening.

And again, I certainly don't want the PHP Group or any other to comment
on the good or bad of plugins being GPL because that is entirely
irrelevant. I just sincerely believe that their technical resoning is
entirely wrong.

Thanks,
Martin

[Jerry Stuckle]

Martin Larsen wrote:

Jerry Stuckle wrote:

>Martin Larsen wrote:

>>Is there a way to contact the PHP Group directly?

>Why?

If you understood the technology, the answer would be clear. Rather,
I suggest you visit your local library or bookstore and find out how
interpreters work.

Ok, I will tell you why. I had hoped it was not necessary, but here it
is...

I do in fact know how interpreters work. I have actually written one
myself. Being a professional windows programmer for ages, I have also
learned the hard way the distinct difference between dynamic and static
libraries: missing DLL files on the end user's computer preventing the
programs from even starting.

Wow. A WINDOWS programmer. So you've been programming for what - 15
years, maybe? And you've programmed for ONE OS? Wow.

And you wrote an interpreter? Golly, Gee, Batman. I guess that makes
you an expert on everything! ROFLMAO!

I deliberately asked the question in a simple minded manner as I did not
want my own view of the matter to bias the replies. The thing is that
the core team behind a major CMS (Joomla) has recently changed their
mind about non-GPL plugins (or scripts, if you like). Until then they
accepted and welcomed proprietary plugins, but now they say that since
the CMS is GPL, the plugins must also be GPL to comply.

You got answers to the question you asked.

Now, I don't wish this thread to be for or against GPL. I only want to
discuss the reasoning behind their claims. The point is that they argue
that most extensions are *derivative work* of the CMS (even though they
normally don't include a single line of code from it) because they are
statically linked to the CMS. If they were dynamically linked, the
matter would be different.

This has nothing to do with PHP programming. I suggest you take it over
to the Joomla newsgroup.

Yep, that is what they say. While you and I can agree that it doesn't
make much sense to talk about linking for interpreters, they
nevertheless use it in their argumentation. And that is why I asked the
question: Are PHP libraries linked dynamically or statically?

That's their problem. If you understood as well as you say, you would
have the answer to your question.

In my opinion they make two mistakes: the first is to talk about linking
at all, the second is to claim that the plugins are statically linked.

That could be. But it's not a topic for this newsgroup.

As I see it, even when we are not really talking linking, the
characteristics of the processes involved in the INCLUDE more closely
resembles dynamic linking than static linking. Which means that their
argumentation is wrong no matter what.

It resembles INCLUDES. It has nothing to do with linking.

As it happens, we (third-party developers for Joomla) have tried hard to
make them see that their arguments are wrong. But they keep claiming
that the scripts are statically linked and thus derivative works of the
CMS.

Then build your own CMS.

And now to my question: Is there a way to contact the PHP Group directly?

Why? They can't change Joomla's mind, either. Nor are they going to
change Joomla's terminology.

I have an idea that if we could get a "official" statement of the
linking or non-linking involved, they might be more prone to listening.

This has nothing to do with their use of terminology. It is a licensing
issue, and they have a write to require licenses for their CMS to follow
their rules.

And again, I certainly don't want the PHP Group or any other to comment
on the good or bad of plugins being GPL because that is entirely
irrelevant. I just sincerely believe that their technical resoning is
entirely wrong.

You're discussing legal issues, and should be talking to an attorney.
But historically Joomla is on solid legal ground. The terminology they
use is not important. The fact your tools ARE derivative works is.

Thanks,
Martin

Please don't bring your argument over here. We're not interested.
--
=============== ===
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attgl obal.net
=============== ===

[Martin Larsen]

Jerry Stuckle wrote:

Wow. A WINDOWS programmer. So you've been programming for what - 15
years, maybe? And you've programmed for ONE OS? Wow.

And you wrote an interpreter? Golly, Gee, Batman. I guess that makes
you an expert on everything! ROFLMAO!

Excuse me, but why are you flaming like this? Did I ever call myself an
expert? Did I ever use bad language or something? Did I ever call you
stupid things? Was I ever impolite?

I really can't understand why so many people in these newsgroups are so
hostile to each other. I think you should apologize, but I don't expect
that you will.

The terminology they
use is not important. The fact your tools ARE derivative works is.

Aha. A fact?

Then please tell me why it is a fact.

Sincerely,
Martin

[Andy Hassall]

On Mon, 23 Jul 2007 11:40:02 +0200, Martin Larsen
<ma************ ********@bigfoo t.comwrote:

>And now to my question: Is there a way to contact the PHP Group directly?

According to license.txt in the PHP distribution:

"The PHP Group can be contacted via Email at gr***@php.net."

I wonder if you might have more luck with Zend, the company behind the core of
PHP (the Zend engine). Since this includes the compiler + bytecode interpreter
anyway, they should be well-placed to answer.

http://www.zend.com/company/contact_us

Have you contacted the FSF as well? Since they produced the GPL license, they
may be able to clarify its terms.

>I have an idea that if we could get a "official" statement of the
linking or non-linking involved, they might be more prone to listening.

And again, I certainly don't want the PHP Group or any other to comment
on the good or bad of plugins being GPL because that is entirely
irrelevant. I just sincerely believe that their technical resoning is
entirely wrong.

If it were "libraries" then I'd interpret it as "dynamic linking" in the
context of the GPL. This seems to be backed up with the already-quoted:

http://www.gnu.org/licenses/gpl-faq....terpreterIsGPL
"Another similar and very common case is to provide libraries with the
interpreter which are themselves interpreted. For instance, Perl comes with
many Perl modules, and a Java implementation comes with many Java classes.
These libraries and the programs that call them are always dynamically linked
together.

A consequence is that if you choose to use GPL'd Perl modules or Java classes
in your program, you must release the program in a GPL-compatible way,
regardless of the license used in the Perl or Java interpreter that the
combined Perl or Java program will run on."
Introducing the term "plugin" seems to point to the following, though:

http://www.gnu.org/licenses/gpl-faq.html#GPLAndPlugins
"If the program dynamically links plug-ins, and they make function calls to
each other and share data structures, we believe they form a single program,
which must be treated as an extension of both the main program and the
plug-ins. This means the plug-ins must be released under the GPL or a
GPL-compatible free software license, and that the terms of the GPL must be
followed when those plug-ins are distributed."
There does seem to be a valid distinction between a library, which implements
a particular function and makes that available to /any/ other application that
loads it, versus a plug-in that explicitly extends one application - which
makes the argument of "derivative work" plausible.

It's not entirely clear, so it's an interesting question.

--
Andy Hassall :: an**@andyh.co.u k :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Martin Larsen]

Andy Hassall wrote:

According to license.txt in the PHP distribution:

"The PHP Group can be contacted via Email at gr***@php.net."

Thanks!

I wonder if you might have more luck with Zend, the company behind the core of
PHP (the Zend engine). Since this includes the compiler + bytecode interpreter
anyway, they should be well-placed to answer.

I think you are right, Zend would be a good source of info.

It's not entirely clear, so it's an interesting question.

Indeed it is.

Thanks for your comments. After getting flamed by Jerry, it was a
pleasence to read a decent post like yours :-)

Martin

[Jerry Stuckle]

Martin Larsen wrote:

Jerry Stuckle wrote:

>Wow. A WINDOWS programmer. So you've been programming for what - 15
years, maybe? And you've programmed for ONE OS? Wow.

And you wrote an interpreter? Golly, Gee, Batman. I guess that makes
you an expert on everything! ROFLMAO!

Excuse me, but why are you flaming like this? Did I ever call myself an
expert? Did I ever use bad language or something? Did I ever call you
stupid things? Was I ever impolite?

You came across as arrogant and self serving. If you weren't trying to
prove yourself an expert, why come up with all of that junk?

I really can't understand why so many people in these newsgroups are so
hostile to each other. I think you should apologize, but I don't expect
that you will.

Probably because you came across as self-serving and arrogant. And no,
I won't apologize for your arrogance.

>The terminology they use is not important. The fact your tools ARE
derivative works is.

Aha. A fact?

Then please tell me why it is a fact.

You want legal advice, talk to an attorney. Any one who is familiar
with computer law will tell you the same thing.

But I know you won't.

Sincerely,
Martin

--
=============== ===
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attgl obal.net
=============== ===

[Sanders Kaufman]

Jerry Stuckle wrote:

Martin Larsen wrote:

>Excuse me, but why are you flaming like this? Did I ever call myself
an expert? Did I ever use bad language or something? Did I ever call
you stupid things? Was I ever impolite?

You came across as arrogant and self serving. If you weren't trying to
prove yourself an expert, why come up with all of that junk?

Sheesh, Jerry! You do this a lot. Your blood sugar gets out of whack
or something and you go BALLISTIC on some poor fool.

Not all of us are here to prove that we're experts.
Some of just like having conversations about things we're interested in.