Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH 0/6] RFC: Typesafe callbacks | Date | Mon, 21 Jan 2008 09:17:30 +1100 |
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On Monday 21 January 2008 00:00:52 Tejun Heo wrote: > What should be do are > > * Check that the threadfn's argument fits into void *.
For everything but timer, you'll get a warning if the data isn't assignable to a void *, so you get a warning if you use a non-pointer already.
But it would be cool to allow functions which take an unsigned long. To do this, I think that would need to be a special case for the data arg (which we'd really want to wrap in a macro), like:
/* If fn expects an unsigned long, cast the data. If not, we'll * get a warning if data is not void * compatible. */ __builtin_choose_expr(__builtin_compatible_p(typeof(1?(threadfn):NULL), int (*)(unsigned long)), (void *)(unsigned long)(data), (data))
> * Trigger overflow in implicit constant conversion warning if the > specified data is too large for the argument type.
Hmm, u64 on 32-bit platforms? I think that will fail the above test: the type of the function ptr will be "int (*)(u64)" and so you'll end up passing data (a u64) to a void * argument, which will elicit a warning...
I'll test this out and see what I can make...
Thanks! Rusty.
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