[Qt-interest] Advices on safer SIGNAL macro

[Johannes Schaub]

I've written myself a custom SIGNAL macro that at compile time checks that 
all parameter types I gave in the signature passed to SIGNAL are known at 
the point of use of SIGNAL:

namespace static_signal_detail {
   template<typename>
   struct take { };
}

#define STATIC_SIGNAL(SIG) (static_signal_detail::take<void(void SIG)>(), \
                            SIGNAL(SIG))


For example it would throw a *compile time* error if in the following, you 
wrote "Ptr" instead of "common::Ptr" (as happened for me today). Using the 
original SIGNAL macro, it would do nothing. Alternatively one could check 
the return value of "connect" and throw / abort, but that would be a runtime 
error, only noticed when the "connect" is actually executed:

   connect(pages, SIGNAL(changed(Ptr)), SLOT(update(Ptr)));

Is there any problem with my version of SIGNAL? I'm searching for advices on 
how to make it better or on how it sucks so bad that I should just burry it 
and move on.