[libhid-discuss] Re: HELP !! Gettting data from usb device using libhid

[Charles Lepple]

On Sep 12, 2006, at 12:55 AM, Himanshu Bafna wrote:

> Few questions regarding GPL/LGPL licesing regarding usage if libhid/ 
> libusb library: -

Please note that libhid is currently covered by the GPL, not the LGPL.

> 1 - What do you mean by keeping our source code as open source.

 From section 3 of the GPL:

"3.  You may copy and distribute the Program (or a work based on it,  
under Section 2) in object code or executable form under the terms of  
Sections 1 and 2 above provided that you also do one of the following:

     a) Accompany it with the complete corresponding machine-readable  
source code, which must be distributed under the terms of Sections 1  
and 2 above on a medium customarily used for software interchange; or,
     b) Accompany it with a written offer, valid for at least three  
years, to give any third party, for a charge no more than your cost  
of physically performing source distribution, a complete machine- 
readable copy of the corresponding source code, to be distributed  
under the terms of Sections 1 and 2 above on a medium customarily  
used for software interchange; or,
     c) Accompany it with the information you received as to the  
offer to distribute corresponding source code. (This alternative is  
allowed only for noncommercial distribution and only if you received  
the program in object code or executable form with such an offer, in  
accord with Subsection b above.) "

In particular, that means that if you do not distribute your program  
to me, then I do not have any rights to the source code. However,  
your customer has the right (under the GPL) to redistribute the  
resulting program, and if they wanted to post it on the internet,  
they could do so, as long as they followed the redistribution terms  
above.

Please note that this is not legal advice, and you should consult a  
lawyer who is familiar with copyright law.

> 2 - Do we have to publish / keep our code somewhere available on  
> internet for that

Yes, if the binary is available on the internet: http://www.gnu.org/ 
licenses/gpl-faq.html#IfLibraryIsGPL

> 3 - Do we have to keep our whole source code as open source or only  
> the part where we have used open source GPL libraries/ driver part...?

The whole program.

This is the major distinction between the GPL, and the LGPL.

http://www.gnu.org/licenses/gpl-faq.html#GPLInProprietarySystem

-- 
Charles Lepple
clepple at ghz.cc