LGPL question

LGPL question

Post by Martin Hanse » Sat, 28 Aug 2004 20:26:27



Hi All

I am writing a repport on LGPL, during the review of this report, i recieved
a question.

 Well in an embeddet device you do not always have acces to the software. So
how to comply with the term in 6.b (2) (quotetd below) of the LGPL?
 I have to make sure that my propetarely work will work with a modified
version of the libary. well teknikaly this is not an issue. But if my
software is deliveres in a ROM. The user cannot put in a new libary!
Do I the have to supply my own work on some other media, for the user to
take this and dynamicaly relink my work with a new version of the libary. I
don't know what he/she will use it for as he/she cannot put it back in the
ROM.

 Or is it sufficient to deliver the sources of the library (or an written
offer to do so). And then just make sure that my work in theory could work
with a modified version if one could get that into the ROM?

LGPL 6
...
b) Use a suitable shared library mechanism for linking with the Library. A
suitable mechanism is one that (1) uses at run time a copy of the library
already present on the user's computer system, rather than copying library
functions into the executable, and (2) will operate properly with a
modified version of the library, if the user installs one, as long as the
modified version is interface-compatible with the version that the work was
made with.
...

NB: for people remembering my former questions on the distribution
definiotion, who got mad becuase they thought that i was trying to steel
LGPL code. I can relax you that even thoug i have not had this question
cleared (no answer from FSF). My report will still say that any sale or
hire of devices is a distribution. Actually i do not discuss it in the
repport, it would only leed to the wrong ideas.

--
Martin Hansen

 
 
 

LGPL question

Post by Devlor Nakart » Sun, 29 Aug 2004 21:46:51



> Hi All

> I am writing a repport on LGPL, during the review of this report, i recieved
> a question.

>  Well in an embeddet device you do not always have acces to the software. So
> how to comply with the term in 6.b (2) (quotetd below) of the LGPL?
>  I have to make sure that my propetarely work will work with a modified
> version of the libary. well teknikaly this is not an issue. But if my
> software is deliveres in a ROM. The user cannot put in a new libary!
> Do I the have to supply my own work on some other media, for the user to
> take this and dynamicaly relink my work with a new version of the libary. I
> don't know what he/she will use it for as he/she cannot put it back in the
> ROM.

>  Or is it sufficient to deliver the sources of the library (or an written
> offer to do so). And then just make sure that my work in theory could work
> with a modified version if one could get that into the ROM?

> LGPL 6
> ...
> b) Use a suitable shared library mechanism for linking with the Library. A
> suitable mechanism is one that (1) uses at run time a copy of the library
> already present on the user's computer system, rather than copying library
> functions into the executable, and (2) will operate properly with a
> modified version of the library, if the user installs one, as long as the
> modified version is interface-compatible with the version that the work was
> made with.
> ...

> NB: for people remembering my former questions on the distribution
> definiotion, who got mad becuase they thought that i was trying to steel
> LGPL code. I can relax you that even thoug i have not had this question
> cleared (no answer from FSF). My report will still say that any sale or
> hire of devices is a distribution. Actually i do not discuss it in the
> repport, it would only leed to the wrong ideas.

IANALGPLE, but I would say that your proprietary work simply has to use
library functions in such a way that when the library changes, as long as
the new library has the same interface to those functions, your program
will still work with the new version.

So you link to functions A and B in the library, and it gets updated, so
the functions are now C and R, but A and B calls will still access them,
and they're functionally similar(maybe faster or accurate to more
decimals, or work with a different architecture, etc) so your program can
still use the new library and operate correctly.

Given that libraries are updated independent of all sorts of software
using them, most likely they will remain compatible for a long time to
come.  If years from now some library update breaks your software, it's a
matter of if you have the resources, and/or a commitment to, update your
software to be compatible with the new library as well.

So yes, it is sufficient to be sure in theory that your program could work
with a modified version of the library, unless you made a contract
promising more.

 
 
 

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