I've raised this topic once, still...

I don't understand why null should be casted to whatever
type you want other than void*? It's so annoying! Just
look around, no other language has such a restriction:
C, C++, Pascal, BASIC... It gets especially #%#@ when
calling WinAPI functions, since many arguments are
usually nulls. Just let null be compatible with any pointer
type. Or, even better, make void* compatible with all
pointers, like it was in C.

You're probably right. -Walter

"Pavel Minayev" <evilone@omen.ru> wrote in message news:a0044r$1m2p$1@digitaldaemon.com...
> I've raised this topic once, still...
>
> I don't understand why null should be casted to whatever
> type you want other than void*? It's so annoying! Just
> look around, no other language has such a restriction:
> C, C++, Pascal, BASIC... It gets especially #%#@ when
> calling WinAPI functions, since many arguments are
> usually nulls. Just let null be compatible with any pointer
> type. Or, even better, make void* compatible with all
> pointers, like it was in C.
>
>

I don't understand. The following works:

object test()
{
    return null;
}

works, as well as object*, int*, etc. Can you please post an example where it doesn't? Thanks!

"Pavel Minayev" <evilone@omen.ru> wrote in message news:a0044r$1m2p$1@digitaldaemon.com...
> I've raised this topic once, still...
>
> I don't understand why null should be casted to whatever
> type you want other than void*? It's so annoying! Just
> look around, no other language has such a restriction:
> C, C++, Pascal, BASIC... It gets especially #%#@ when
> calling WinAPI functions, since many arguments are
> usually nulls. Just let null be compatible with any pointer
> type. Or, even better, make void* compatible with all
> pointers, like it was in C.
>
>

"Walter" <walter@digitalmars.com> wrote in message news:a00pf9$24ri$1@digitaldaemon.com...
> I don't understand. The following works:
>
> object test()
> {
>     return null;
> }
>
> works, as well as object*, int*, etc. Can you please post an example where it doesn't? Thanks!

Try this:

    import windows;

    int main(char[][] args)
    {
     HANDLE x = null;
    }

HANDLE is a typedef for void*, and thus a pointer type, so it should be compatible with null, right? Still it isn't. As the result, when working with API heavily, you have to cast null to HANDLE all the time...

Ok, I see the problem. It'll get fixed. -Walter

"Pavel Minayev" <evilone@omen.ru> wrote in message news:a01g85$2ma7$1@digitaldaemon.com...
> Try this:
>
>     import windows;
>
>     int main(char[][] args)
>     {
>      HANDLE x = null;
>     }
>
> HANDLE is a typedef for void*, and thus a pointer type, so it should be compatible with null, right? Still it isn't. As the result, when working with API heavily, you have to cast null to HANDLE all the time...

I agree about NULL being compatible with other pointer types, but disagree about void* being implicitly convertable to other pointer types.  That leaves a gaping hole in the typechecking safety net that will end up causing bugs.  That is why C++ "fixed" that problem.

Sean

"Pavel Minayev" <evilone@omen.ru> wrote in message news:a0044r$1m2p$1@digitaldaemon.com...
> I've raised this topic once, still...
>
> I don't understand why null should be casted to whatever
> type you want other than void*? It's so annoying! Just
> look around, no other language has such a restriction:
> C, C++, Pascal, BASIC... It gets especially #%#@ when
> calling WinAPI functions, since many arguments are
> usually nulls. Just let null be compatible with any pointer
> type. Or, even better, make void* compatible with all
> pointers, like it was in C.

I fixed D so that null is compatible with other pointer and reference types, but other void*'s will require an explicit cast. -Walter

"Sean L. Palmer" <spalmer@iname.com> wrote in message news:a02rnb$iij$1@digitaldaemon.com...
> I agree about NULL being compatible with other pointer types, but disagree about void* being implicitly convertable to other pointer types.  That leaves a gaping hole in the typechecking safety net that will end up
causing
> bugs.  That is why C++ "fixed" that problem.
>
> Sean
>
> "Pavel Minayev" <evilone@omen.ru> wrote in message news:a0044r$1m2p$1@digitaldaemon.com...
> > I've raised this topic once, still...
> >
> > I don't understand why null should be casted to whatever
> > type you want other than void*? It's so annoying! Just
> > look around, no other language has such a restriction:
> > C, C++, Pascal, BASIC... It gets especially #%#@ when
> > calling WinAPI functions, since many arguments are
> > usually nulls. Just let null be compatible with any pointer
> > type. Or, even better, make void* compatible with all
> > pointers, like it was in C.
>
>
>