[LuaJIT ffi] dynamic loading of DLL functions

[Thomas Lauer <thomas.lauer@...>]

I am trying to call a few Win32 functions which may or may not be
present in the target DLL.

I've found no simple (ie fast) way to check whether a cdef'd function
has actually been found in the relevant namespace. ffi.typeof() etc all
seem to throw an error if the function name could not be resolved. Of
course, I could catch that but I'd assume this scenario is sufficiently
common to warrant some sort of API. Perhaps I did miss something
obvious?

-- 
cheers  thomasl