(Hi Joerg,) On Tue, 2005-12-20 at 16:15 +0100, Hoehle, Joerg-Cyril wrote: > Luis Oliveira > >Let me see if I got this straight, your proposal is that the :pointer > >type may or may not accept NIL (but it should documented as > >non-portable), > No. :pointer is documented to only accept valid CFFI pointers. > These are documented as opaque. > Code using NIL is in error, as well as code using 0.
I agree completely with this. It's easy to define a translator on :pointer to convert NIL to and from null pointers if this is desired. > Another useful addition is a pointer type which does not accept a > null-pointer, but signals an error instead, or just specifies that > "passing (null-pointer) is an error". This type can be used in > function declarations. The effect is two-fold: > a) just from seeing the declaration, you know that NULL is not > allowed. > b) optionally, the transformers could check for this at run-time. I'm not certain I see how you could do this at any other time besides run-time, except for maybe some cases where the function argument is CONSTANTP and evaluates to nil in some compiler-macro or so. This is the sort of stuff that should be easy to define in "userland" using the type translator mechanism, but I can see that this could be usefully predefined by CFFI. James _______________________________________________ cffi-devel mailing list cffi-devel@common-lisp.net http://common-lisp.net/cgi-bin/mailman/listinfo/cffi-devel
