Custom digital filters in GSL

[Vyaas Gururajan]

Hi,

[I know that there are other signal processing libraries out there, but 
my requirements are GSL constrained at the moment.]

I've noted that the Gaussian filter in GSL uses a moving window very 
similar to that used in the moving window statistics framework in GSL. 
The latter seems to have an interface for the user to define their own 
windows. Is something similar possible for digital filtering? If not, 
can someone point me in the right direction to implement something like it?

V