rationale for function and delegate

[Juanjo Alvarez]

On Sat, 16 Oct 2010 14:42:13 +0000 (UTC), dsimcha <dsimcha at yahoo.com> 
wrote:
> delegate with minimal overhead.  This mitigates the situation a 
lot, since if an
> API requires a delegate and you have a function pointer, you just 
do a
> toDelegate(someFunctionPointer).

Sorry for asking here something that should go to D.learn, but how do 
you do the reverse, that is, getting a function from a delegate? I 
need that in my project so I can pass it to signal so some Unix 
signal will trigger a method of an already instantiated object.