On Tue, Jan 31, 2017 at 10:03:01PM +0100, René Scharfe wrote: > > Perhaps we could disallow a side-effect operator in the macro. By > > disallow I mean place a comment at the definition to the macro and > > hopefully catch something like that in code-review. We have the same > > issue with the `ALLOC_GROW()` macro. > > SWAP(a++, ...) is caught by the compiler, SWAP(*a++, ...) works fine. > Technically that should be enough. :) A comment wouldn't hurt, of course.
One funny thing is that your macro takes address-of itself, behind the scenes. I wonder if it would be more natural for it to take pointers-to-objects, making it look more like a real function (i.e., SWAP(&a, &b) instead of SWAP(a, b)". And then these funny corner cases become quite obvious in the caller, because the caller is the one who has to type "&". -Peff
