On 7/29/07, Justin C. Walker <[EMAIL PROTECTED]> wrote: > > > On Jul 29, 2007, at 18:24 , Alec Mihailovs wrote: > > > > > From: <[EMAIL PROTECTED]> > > > >> > >> Not always so. Verbatim snippet from the horse's mouth: > >> > >> > >> "When we say that GPLv2 and GPLv3 are incompatible, it means there > >> is no > >> legal way to combine code under GPLv2 with code under GPLv3 in a > >> single > >> program. This is because both GPLv2 and GPLv3 are copyleft > >> licenses: each > >> of them says, "If you include code under this license in a larger > >> program, > >> the larger program must be under this license too." There is no > >> way to > >> make them compatible. We could add a GPLv2-compatibility clause to > >> GPLv3, > >> but it wouldn't do the job, because GPLv2 would need a similar > >> clause. > >> > >> Fortunately, license incompatibility only matters when you want to > >> link, > >> merge or combine code from two different programs into a single > >> program. > >> There is no problem in having GPLv3-covered and GPLv2-covered > >> programs > >> side by side in an operating system. For instance, the TeX license > >> and the > >> Apache license are incompatible with GPLv2, but that doesn't stop > >> us from > >> running TeX and Apache in the same system with Linux, Bash and > >> GCC. This > >> is because they are all separate programs. Likewise, if Bash and > >> GCC move > >> to GPLv3, while Linux remains under GPLv2, there is no conflict." > >> > >> http://www.gnu.org/licenses/rms-why-gplv3.html > > > > Well, I wouldn't call SAGE a single program. Besides, that's > > exactly what > > commercial CAS's do. In particular, Maple includes gmp and a series > > of other > > programs under separate licenses. > > Isn't 'gmp' a library, rather than a program? One of the GPL issues > for those producing non-GPL'd code is that of libraries: some GPL'd > libraries can be included without "poisoning" the program's > licensing, while others can not. I think it's much "worse" under the > GPL3 "umbrella".
GMP is licensed under the LGPL (which used to be called the Library GPL, but was retroactively named "Lesser" GPL due to confusion). However, anything that is licensed under the normal GPL cannot be linked without "infecting" the main program, be it a library, program, snippet of code, etc... See http://clisp.cvs.sourceforge.net/*checkout*/clisp/clisp/doc/Why-CLISP-is-under-GPL for more details on this. As far as I know, GPLv3 doesn't really affect this property of the license. The main difference is that GPLv3 will prevent you from making your own modifications to a GPLv3'd program, releasing the source, but then ensuring (through a digital signature scheme) that it cannot run on the hardware you distributed it with. -Bobby > Justin > > -- > Justin C. Walker, Curmudgeon-At-Large > Institute for the Absorption of Federal Funds > -------- > If you're not confused, > You're not paying attention > -------- > > > > > > > -- Bobby Moretti [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---