[cairo] Re: License for cairo changed to LGPL

Bill Spitzak spitzak at d2.com
Wed Aug 4 11:55:37 PDT 2004

On Tuesday 03 August 2004 08:40 pm, Carl Worth wrote:
>       3) I'm not convinced it's actually necessary or beneficial. It
>            seems to me that the LGPL already makes sufficient provision
>            for static linking. It simply requires the distributor to
>            provide (or make a written offer to provide) object code so
>            that the user can relink with a modified version of the
>            library, (see 6.a).
>            Can someone show me an actual case where that burden is so
>            onerous as to outweigh any advantage that might come from
>            using cairo?

The LGPL requirement that relinking be possible was designed for glibc, and 
does not work in practice for under-development and/or optional libraries, 
such as Cairo and virtually all other GUI tools.

The LGPL effectively requires that users of the software have access to the 
source (though it can be under NDA). Nothing prevents somebody from making a 
"modified version" of Cairo that is not binary compatable. But according to 
the LGPL they must be able to "relink" the program with the modified version 
of Cairo. This cannot be done except by recompiling the program. This means 
the user has the source (unless the author makes some sort of promise in 
perpeturary to recompile the code for any version of Cairo sent to them).

Such "relinking" is also physically impossible on a device with the program 
in ROM, even if everything was GPL. It is probably best to make sure nobody 
thinks that the license outlaws that.

It is many times easier to reverse-engineer object files or a program using 
shared libraries, which is certainly a concern for some.

The inability to statically link is also a huge practical problem for a 
library like Cairo that is not necessarily already on the machine. It means 
any program using Cairo has to be "installed" and thus eliminates the abilty 
to use it in the small types of programs that are needed to get it popular.

I fully agree with most of the posters here that the LGPL will not work for 
Cairo without FOX/FLTK style exceptions.

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