R SIG Debian - Nov 2016 - Ubuntu 16.10 Yakkety Yak uses GCC 6 but -std=c++98 is missing

On 12 November 2016 at 22:54, Kirill M?ller wrote:

[... lots of stuff deleted ...]

| I noticed this because plogr logging crashed in dplyr (compiled with gcc 
| 6) right after upgrading to yakkety; I still had a gcc-5 built version 
| of Rcpp installed. As soon as I added -std, everything worked as before. 
| No minimal example, sorry. Don't we need "-std=c++98" in
Makevars
| anyway, even if it's just to avoid users using C++11 constructs and then 
| wondering why their packages fail on CRAN?

There is still no minimally preproducible example here; just a (pardon me
here) rambling description of a hasty system upgrade.

It is _somewhat common_ to have to recompile C++ shared objects when compiler
major versions change.

So I am unsure if we have actually demonstrated a bug here.

Dirk

-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org

On 13.11.2016 00:00, Dirk Eddelbuettel wrote:
> On 12 November 2016 at 22:54, Kirill M?ller wrote:
>
> [... lots of stuff deleted ...]
>
> | I noticed this because plogr logging crashed in dplyr (compiled with gcc
> | 6) right after upgrading to yakkety; I still had a gcc-5 built version
> | of Rcpp installed. As soon as I added -std, everything worked as before.
> | No minimal example, sorry. Don't we need "-std=c++98" in
Makevars
> | anyway, even if it's just to avoid users using C++11 constructs and
then
> | wondering why their packages fail on CRAN?
>
> There is still no minimally preproducible example here; just a (pardon me
> here) rambling description of a hasty system upgrade.
>
> It is _somewhat common_ to have to recompile C++ shared objects when
compiler
> major versions change.
>
> So I am unsure if we have actually demonstrated a bug here.
Don't we need "-std=c++98" for GCC 6 in Makevars anyway, even if
it's
just to save users from using C++11 constructs and then wondering why 
their packages fail on CRAN/winbuilder? In my case it also saves me from 
recompiling "all of CRAN" (at least for now); that's a nice side
effect,
but the first part also looks important to me.


-Kirill

On 13 November 2016 at 00:13, Kirill M?ller wrote:
| On 13.11.2016 00:00, Dirk Eddelbuettel wrote:
| > On 12 November 2016 at 22:54, Kirill M?ller wrote:
| >
| > [... lots of stuff deleted ...]
| >
| > | I noticed this because plogr logging crashed in dplyr (compiled with
gcc
| > | 6) right after upgrading to yakkety; I still had a gcc-5 built version
| > | of Rcpp installed. As soon as I added -std, everything worked as
before.
| > | No minimal example, sorry. Don't we need "-std=c++98" in
Makevars
| > | anyway, even if it's just to avoid users using C++11 constructs and
then
| > | wondering why their packages fail on CRAN?
| >
| > There is still no minimally preproducible example here; just a (pardon me
| > here) rambling description of a hasty system upgrade.
| >
| > It is _somewhat common_ to have to recompile C++ shared objects when
compiler
| > major versions change.
| >
| > So I am unsure if we have actually demonstrated a bug here.
| Don't we need "-std=c++98" for GCC 6 in Makevars anyway, even if
it's
| just to save users from using C++11 constructs and then wondering why 
| their packages fail on CRAN/winbuilder? In my case it also saves me from 
| recompiling "all of CRAN" (at least for now); that's a nice side
effect,
| but the first part also looks important to me.

It's a fair, and open, question.

We may, and then we may get away with not rebuilding; or we may not, but then
have to pay by rebuilding all.

I am somewhat surprised I haven't been asked to rebuild Debian packages.
There too we do have binary depends on C++ packages from CRAN, ie r-cran-rcpp
and r-cran-dplyr and whatnot.  But then ... then Debian archive managers now
just do 'binary rebuilds' as needed and I may be out of the loop.

Sorry but I just don't have much better information. There are Debian Wiki
pages on g++ transitions...

Dirk

-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org