error: 'override' does not name a type

[Johannes Ring]

The following error occurs when using GCC 4.6.3 on Ubuntu 12.04:

[  1%] Building CXX object dolfin/CMakeFiles/dolfin.dir/ale/HarmonicSmoothing.cpp.o
cd /root/.hashdist/tmp/dolfin-srrc24didmpr-1/_build/dolfin && /usr/bin/c++   -DDOLFIN_LA_INDEX_SIZE=4 -DDOLFIN_SIZE_T=8 -DDOLFIN_VERSION=\"1.7.0dev\" -DHAS_CHOLMOD -DHAS_HDF5 -DHAS_MPI -DHAS_OPENMP -DHAS_PARMETIS -DHAS_PETSC -DHAS_SCOTCH -DHAS_SLEPC -DHAS_UMFPACK -DHAS_VTK -DHAS_ZLIB -DNDEBUG -D_BSD_SOURCE -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -Ddolfin_EXPORTS -pedantic -std=c++0x  -Wno-deprecated   -fopenmp -O3 -DNDEBUG -fPIC -I/root/.hashdist/tmp/dolfin-srrc24didmpr-1/_build -isystem /root/.hashdist/bld/vtk/epjczt5gfrl4/include/vtk-5.10 -I/root/.hashdist/tmp/dolfin-srrc24didmpr-1 -I/root/.hashdist/bld/ffc/kozfm5iocx7o/include -I/root/.hashdist/bld/slepc/p32krb7j7gra/include -isystem /root/.hashdist/bld/suitesparse/fnd3oyibysp3/include/suitesparse -isystem /root/.hashdist/bld/scotch/vm3qczcxeszc/include -I/root/.hashdist/bld/zlib/v6anirfvk2op/include -isystem /root/.hashdist/bld/mpi/gmkx3ftk3tz2/include -isystem /root/.hashdist/bld/eigen/fbpvjm676wjr/include/eigen3 -isystem /root/.hashdist/bld/boost/qhpnxhtx5tl7/include -isystem /root/.hashdist/bld/hdf5/nr5pdm6zckjw/include -isystem /root/.hashdist/bld/petsc/vvqd7cxwcd4j/include -isystem /root/.hashdist/bld/superlu_dist/y3byj5cqyt3n/include -isystem /root/.hashdist/bld/hypre/kh4vd5dptalu/include -isystem /root/.hashdist/bld/parmetis/opckbggomu7w/include -isystem /root/.hashdist/bld/libxml2/mlk7x2dhjiud/include    -o CMakeFiles/dolfin.dir/ale/HarmonicSmoothing.cpp.o -c /root/.hashdist/tmp/dolfin-srrc24didmpr-1/dolfin/ale/HarmonicSmoothing.cpp
In file included from /root/.hashdist/tmp/dolfin-srrc24didmpr-1/dolfin/ale/HarmonicSmoothing.cpp:33:0:
/root/.hashdist/tmp/dolfin-srrc24didmpr-1/dolfin/ale/Poisson1D.h:46:31: error: expected ';' at end of member declaration
/root/.hashdist/tmp/dolfin-srrc24didmpr-1/dolfin/ale/Poisson1D.h:46:33: error: 'override' does not name a type
...

It turns out that the override keyword is not supported in GCC 4.6, but we accept this version in CMakeLists.txt. Should we fix this error or should we bump the minimum required GCC version to 4.7? I guess the latter, since we are no longer testing with GCC 4.6 on the buildbot.

[Martin Sandve Alnæs]

Can we bump to gcc 4.8? That gives us "Inheriting constructors" and "Alignment support" which could both be useful:

https://gcc.gnu.org/projects/cxx0x.html

It's standard practice now to build new compilers on clusters with ancient toolchains anyway. Ubuntu 14.04 LTS has 4.8.2.

[Prof Garth Wells]

@martinal Suggested version bump is fine with me.

[Martin Sandve Alnæs]

Do we document the required compiler version anywhere? Otherwise there's nothing to do here.

[Jan Blechta]

Do we document the required compiler version anywhere?

In release notes paper, https://bitbucket.org/fenics-project/fenics-release-notes/src/55e694438d308c2ae0c02aea9d61ae57f62a025a/v1.7/paper/paper.tex?at=master&fileviewer=file-view-default#paper.tex-131. But I don't think we have decided to continue publishing it in any way. Anyway committing it there is almost no-op.

[Anders Logg (Chalmers)]

Removing milestone: 1.7 (automated comment)

[Jan Blechta]

Now GCC >= 4.8.3 is required.