Thanks, that was very helpful. The C11 features I use do actually work in C99 mode, so I will stick with that. I just thought it was kind of "cleaner" to specify C11 mode when using features from that standard.
2020-09-29 16:35 GMT+02:00 "Prof Brian Ripley" <rip...@stats.ox.ac.uk>: > On 28/09/2020 12:44, Andreas Kersting wrote:> Hi, >> > what is the correct way to specify a C standard in a package's Makevars >> > file? >> > Building a package with e.g. PKG_CFLAGS = -std=gnu11 does work but R CMD >> > check issues a warning: > > for some unstated value of 'work' ... > >> * checking compilation flags in Makevars ... WARNING >> Non-portable flags in variable 'PKG_CFLAGS': >> -std=gnu11 >> > (Same for -std=c11.) >> > Thanks! Regards, >> Andreas Kersting > > Those flags are not portable, as 'check' correctly says. Furthermore, on > some platforms there may be no flag which can be added -- R documents that > 'CC' specifies a C99 compiler, and that or CC+CFLAGS are likely to specify > flags which are incompatible with -std=c11 (true on Solaris where -xc99 is > used). > > So, like all such overrides (see 'Writing R Extensions') you need to write a > configure script (preferably using autoconf) to > > - select an appropriate C compiler+flags > - substitute them into src/Makefile.in > > For the new features I have used in C11, all known compilers make them > available in C99 mode and a configure script could be used to test for their > presence (as R itself does). That is, it is rare to actually need to specify > C11 mode. > > -- > Brian D. Ripley, rip...@stats.ox.ac.uk > Emeritus Professor of Applied Statistics, University of Oxford > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
