Re: [PATCH 1/5] add SWAP macro

Am 30.01.2017 um 22:03 schrieb Johannes Schindelin:

It is curious, though, that an
expression like "sizeof(a++)" would not be rejected.

Clang normally warns about something like this ("warning: expression 
with side effects has no effect in an unevaluated context 
[-Wunevaluated-expression]"), but not if the code is part of a macro.  I 
don't know if that's intended, but it sure is helpful in the case of SWAP.

Further, what would SWAP(a++, b) do? Swap a and b, and *then* increment a?

That might be a valid expectation, but GCC says "error: lvalue required 
as unary '&' operand" and clang puts it "error: cannot take the address 
of an rvalue of type".

René