[hpsdr] libusb and GPL (was PlayStation 3)

[Bill Tracey]

Actually libusb-win32 had an access DLL, driver, installer and other 
gorp.  The access DLL appears to be under the LGPL (see: 
http://libusb-win32.sourceforge.net/#license ) while the rest is under the 
GPL.  So I think you'd be able to talk to Ozy/Janus using the LGPL'd libsub 
dll and not incur the obligations of the GPL in your program that uses that 
DLL.

My (non lawyer,  software professional) understanding of the (L)GPL is that 
the obligations of the GPL do not end at a DLL boundary, but at a process 
boundary.  That is the GPL is defined in terms of a program, and most 
interpretations I've gotten on the meaning of program in the context of the 
GPL is that which is in a single process's address space.  So if you have 
an .exe that uses a GPL'd DLL (or has GPL code embedded into it)  all of 
the code accessed by the process is subject to the GPL (with some 
exceptions for compiler and system libraries as called out in the 
GPL).    Things that are in the kernel (transistion to supervisor mode) are 
not subject to the GPL because they are not considered to be a part of the 
process.

Others have different interpretations, this the advice I've gotten using 
(L)GPL code in commercial projects and I've had a hard time arguing the 
definition of program so I've come to accept this interpretation   If it 
really matters to you, contact a good IP Lawyer might be in order.

Cheers,

Bill  (kd5tfd)


At 10:05 AM 12/10/2006, Alberto I2PHD wrote:
>***** High Performance Software Defined Radio Discussion List *****
><...snip...>

>Seriously, while we are at this, I have a question to you, GPL gurus...
>
>I understand Ozy can be accessed rather easily under Windows by using the 
>libusb library.
>Unless I am wrong libusb is GPLed.
>What if I write a DLL that uses libusb, and I release the source code of 
>that DLL under the GPL terms ?
>Could I then call that DLL from another program which is not GPLed ?
>Or this can be done only with the LGPL licensing scheme ? And, supposing 
>this last statement is true, what about
>releasing libusb under LGPL ?
>
>Comments ?  Thanks.
>
>73  Alberto  I2PHD



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