Denis

i changed `constexpr` to `const` and it now compiles. `ctests` are all passed OK.

``` bertini@lxbk0596:~/softw/openpmd-build > make VERBOSE=1 /cvmfs/vae.gsi.de/centos7/spack-0.17/opt/linux-centos7-zen/gcc-8.1.0/cmake-3.21.4-hieqyppn4h646bts2yxllx4p2wi5njhq/bin/cmake -S/u/dbertini/softw/openpmd-api -B/u/dbertini/softw/openpmd-build --check-build-system CMakeFiles/Makefile.cmake 0 /cvmfs/vae.gsi.de/centos7/spack-0.17/opt/linux-centos7-zen/gcc-8.1.0/cmake-3.21.4-hieqyppn4h646bts2yxllx4p2wi5njhq/bin/cmake -E cmake_progress_start /u/dbertini/softw/openpmd-build/CMakeFiles /u/dbertini/softw/openpmd-build//CMakeFiles/progress.marks make -f CMakeFiles/Makefile2 all make[1]: Entering directory `/u/dbertini/softw/openpmd-build' make -f CMakeFiles/openPMD.dir/build.make CMakeFiles/openPMD.dir/depend make[2]: Entering...

reinforcing compilation with ` cmake . -DCMAKE_CXX_FLAGS=-std=c++14` or `c++17` does not help, always the same compilation error

It is `gcc8.1.01` installed over a native `centos7` OS with `gcc4.8` as native compiler. Yes the replacement of `constexpr` to `const` solved the issue

humm, do you think it is a problem linked to the GCC compiler, `gcc 8.1` being too old ?

Yes i also think so, then may be some `cxx_flags` are missing ?

what is the shareRaw() function exactly doing ?

ah ok thx !

may be you can help, i would like to extend the following example for parallel writing for particle ``` { // open file for writing Series o = Series( "/lustre/rz/dbertini/otest/openpmd-api.h5",...

I tried something like ``` ParticleSpecies &e = series.iterations[1].particles["e"]; auto const value = double(mpi_size); std::vector local_data(100, value); //for (int k=0; k