[Cin] stdc++11 detecion via autotools

[Phyllis Smith]

Andrew,
Your research is helpful as it is something we do not have time to do.  I
am going to try to summarize some of your suggestions and add that to the
manual.  That way we can have BOTH the stable builds for the users AND
provide good suggestions for the more computer savvy users who do their own
builds.  For example, if someone wants to build the latest dav1d because of
the significant speedup in 10/12 bit decoding on ARMv8 cpu-s (up to 2.5
times faster than version 0.5.2) and optimizations on all platforms, they
can upgrade their NASM and do so.

It is so easy to keep the manual updated now that it is in Latex so I can
incorporate your discoveries as they become relevant or obsolete.   So when
you find something interesting and pertinent to Cinelerra, keep passing it
along!  gg/Phyllis



On Fri, Mar 20, 2020 at 8:43 AM Andrew Randrianasulu <
randrianasulu at gmail.com> wrote:

>
>
> I just added AX_CXX_COMPILE_STDCXX_11
> into configure.ac, and now, ./configure prints:
>
>
> checking whether g++ supports C++11 features by default... no
> checking whether g++ supports C++11 features with -std=gnu++11... yes
>
> found  this tip via stackoverfolw, and then gnu site:
> https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
>
> on debian you might want to install autoconf-archive ... or at least some
> says so:
> https://stackoverflow.com/questions/11909347/autotools-check-for-c11
>
> "To get it to work, I also installed autoconf-archive ..[...]"
>
> so, at the end of config.log it says:
>
> CXXFLAGS='-g -O2 -std=gnu++11' but I haven't tested this yet
> I forgot to re-add this png_set_swap thing, so I better to do some other
> tests
> before yet another rebuild :}
>
> just in case:
> https://gcc.gnu.org/projects/cxx-status.html
>
> C++11 Support in GCC
> GCC 4.8.1 was the first feature-complete implementation of the 2011 C++
> standard, previously known as C++0x.
> This mode can be selected with the -std=c++11 command-line flag, or
> -std=gnu++11 to enable GNU extensions as well.
>
> C++14 Support in GCC
> GCC has full support for the previous revision of the C++ standard, which
> was published in 2014.
> This mode is the default in GCC 6.1 and above; it can be explicitly
> selected with the -std=c++14
> command-line flag, or -std=gnu++14 to enable GNU extensions as well.
>
> because new OpenEXR compiles with gcc 5.5.0 as in Slackware 14.2 I assume
> support for  this c++14
> mode was complete enough for  this library even in late gcc 5.x (see
> tables at link above)
>
> Thing is, failing whole Cin build due to one embedded library probably not
> best thing to do ...
> so, just set building new OpenEXR to No in one specific case, when
> compiler has no support  for c++11 at all?
>
> Apparently, static libraries have both advantages (less dependencies for
> run time) and disadvantages
> (if you hit bug in statically-linked lib you are forced to rebuild whole
> thing anyway)
>
> By the way, I think current README in root of Cinelerra source tree
> explain situation fairly well.
> Just for making software BOTH feature complete and  runnable on old
> distros/cpus someone
> has to put some effort .... I hope my little researches help  more than
> hurt.
> --
> Cin mailing list
> Cin at lists.cinelerra-gg.org
> https://lists.cinelerra-gg.org/mailman/listinfo/cin
>
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