On 03.06.25 06:51, Michael Paquier wrote:
> Dropping VS 2015 and going up to VS 2019 brings other benefits,
> __VA_ARGS__ coming in mind.
Yes, this was going to be my next step. As we're already talking about
it, here is my proposed patch.
For an explanation, the background is that MSVC has a "traditional"
preprocessor and a new "conforming" one. The latter is available
starting in VS 2019, but it's not the default. We have some code,
especially around __VA_ARGS__ that specifically caters to this
traditional preprocessor.
Turning on C11 mode in MSVC (/std:c11) automatically turns on the
conforming preprocessor, which would currently break compilation on MSVC
because the code expects it to be in traditional mode.
So my first patch is that we fix that bit and turn on just the
conforming preprocessor (/Zc:preprocessor), without turning on C11 yet.
That way, we get that part out of the way, and we update the
documentation about requiring VS 2019. (And we'd flush out anyone who
might still be running pre-VS-2019 build jobs somewhere.) Later, when
we turn on C11, we can remove the explicit /Zc:preprocessor option again.
(An alternative approach would be to turn on C11 and add another option
to explicitly turn the traditional preprocessor back on, but that seems
pointless, and the documentation also suggests that that combination is
not well supported.)
So the attached patch is my proposal to commit early in PG19.
