[sane-devel] Please give me some help to solve the license issues in using sane

Alessandro Zummo azummo-lists at towertech.it
Fri Jun 6 14:36:39 UTC 2008

On Fri, 6 Jun 2008 10:26:04 -0400
"m. allan noah" <kitno455 at gmail.com> wrote:

> no, the GPL is all about derivative works and combining code, it makes
> no difference the direction:

 You are probably right, the closest entry in the faq that describes this situation
 seems to be http://www.gnu.org/licenses/gpl-faq.html#GPLAndPlugins

    It depends on how the program invokes its plug-ins. If the program uses fork and exec to invoke plug-ins, then the plug-ins are separate programs, so the license for the main program makes no requirements for them.

    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.

    If the program dynamically links plug-ins, but the communication between them is limited to invoking the `main' function of the plug-in with some options and waiting for it to return, that is a borderline case. 

 So, for example, if a GPL backend uses a closed source "plugin"
 to decode the received data, that would be a borderline case.


 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy


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