[PD] gpl vs creative commons

[marius schebella]

Hans-Christoph Steiner wrote:
> On Jan 28, 2008, at 3:45 AM, Frank Barknecht wrote:
> 
>> Hallo,
>> Damian Stewart hat gesagt: // Damian Stewart wrote:
>>
>>> then there's the question of whether any and all Pd patches are  
>>> 'derived
>>> works' (derived from Pd) or '[a combination of] two modules into one
>>> program' and therefore need to be GPL.
>> Pd isn't GPL, so even if patches were derived from it, you'd be fine
>> in that regard.
> 
> Most externals are GPL'ed (and therefore Pd-extended too), so there  
> you have to watch.

does this mean it makes a difference if I use a library from within 
pd-extended or install it myself?
from my understanding GPL is more restrictive than the Pd license (BSD). 
because it forces me to publish whatever I create under GPL again.
does working with a library that is gpl force me to open source my pd 
patch? is a pd patch a derived software at all? and if yes, which are 
the libraries that can be used without problems?
marius.