On 2017-09-28 20:01:37 -0400, Tom Lane wrote:
> I wondered how pervasive this behavior is. AFAICS it is *not* required
> by the C standard; C99 does not say that the left operand of assignment
> must be evaluated first, in fact it says that the order of evaluation is
> unspecified.
FWIW, it's being specificied in C++17 ([1]), which seems to make it not
unlikely to end up in C as well.
> but it does suggest that this is worth fixing, and is not just an artifact
> of an old compiler version.
+1, I saw the same in a bleeding edge c++ version.
Greetings,
Andres Freund
[1] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0145r3.pdf