mpich-default: "error: Aborting because C++ compiler does not work"

[Schamschula (Marius Schamschula)]

While installing an octave package under Mojave (Xcode 10.3), after installing libgcc9 and gcc9,

I get

configure:46412: error: Aborting because C++ compiler does not work.  If you do not need a C++ compiler, configure with --disable-cxx

This is the second machine with this error. Full log attached.

[dstrubbe (David Strubbe)]

I'm not sure this is a problem of mpich per se. The key lines are:

configure:46366: checking whether the C++ compiler /usr/bin/clang++ can build an executable
configure:46395: /usr/bin/clang++ -o conftest  -pipe -stdlib=libstdc++ -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk -arch x86_64  -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_mpich/mpich-default/work/mpich-3.3.1/src/mpl/include -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_mpich/mpich-default/work/mpich-3.3.1/src/mpl/include -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_mpich/mpich-default/work/mpich-3.3.1/src/openpa/src -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_mpich/mpich-default/work/mpich-3.3.1/src/openpa/src -D_REENTRANT -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_mpich/mpich-default/work/mpich-3.3.1/src/mpi/romio/include -Wl,-headerpad_max_install_names -Wl,-syslibroot,/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk -arch x86_64 conftest.cpp  >&5
clang: warning: libstdc++ is deprecated; move to libc++ [-Wdeprecated]
warning: include path for stdlibc++ headers not found; pass '-stdlib=libc++' on the command line to use the libc++ standard library instead [-Wstdlibcxx-not-found]
1 warning generated.
ld: library not found for -lstdc++
clang: error: linker command failed with exit code 1 (use -v to see invocation)
configure:46395: $? = 1

[Schamschula (Marius Schamschula)]

I don't know. However, before ​https://github.com/macports/macports-ports/commit/3378f68291ca0e1a1a6ce793d907b19c77a57184 everything worked.

[gjolleyrogers (Garry Jolley-Rogers)]

+1.

Encountered after I decided to reinstall all ports fresh. osx 10.14 Xcode 11.

double plus frustrating.

[jmroot (Joshua Root)]

[31b04db7a19d7d0b5b9952943094cbca2620723e/macports-ports] added the stdlib setting. I guess that change wasn't correct for all cases if it's being used with clang and not just macports-gcc.

[jmroot (Joshua Root)]

#59330 reported a very similar problem with openmpi.

[willic3 (Charles Williams)]

I believe that this ticket is similar to, but not identical to #59330. For that ticket, I believe that 'cxx_stdlib' is being set to 'libstdc++' in the compilers PortGroup (I may be wrong about this). Is there a way to determine where these variables are being set?

[rubendibattista (Ruben Di Battista)]

I'm also hitting this problem.

Do the updates to ports get checked with build bots? Shouldn't this had been caught during build tests?

[rubendibattista (Ruben Di Battista)]

diff --git a/_resources/port1.0/group/compilers-1.0.tcl b/_resources/port1.0/group/compilers-1.0.tcl
index 9fc68b4c8fa..d4b0435fab8 100644
--- a/_resources/port1.0/group/compilers-1.0.tcl
+++ b/_resources/port1.0/group/compilers-1.0.tcl
@@ -116,7 +116,7 @@ foreach v ${gcc_versions} {
     set cdb(gcc$v,fc)       ${prefix}/bin/gfortran-mp-$compiler_version
     set cdb(gcc$v,f77)      ${prefix}/bin/gfortran-mp-$compiler_version
     set cdb(gcc$v,f90)      ${prefix}/bin/gfortran-mp-$compiler_version
-    set cdb(gcc$v,cxx_stdlib) libstdc++
+    set cdb(gcc$v,cxx_stdlib) libc++
 }
 
 set clang_versions {33 34 37 39 40 50 60 70 80 90}
 

This fix the configure problem. For what I can understand in the code of compilers.tcl, that cxx_stdlib option should not be set if compiling with clang. So I don't get why it actually happens.

[willic3 (Charles Williams)]

This fix makes perfect sense to me, because the fortran compilers won't care about the setting, and the clang compilers require libc++. This is much better than my temporary (and non-portable) fix, which involved setting CXXFLAGS for the configure arguments.

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

Using the compilers PG, the variant gccX can have two different meanings:

1. Use GCC for all compilers (C, C++, etc.)
2. Use GCC for Fortran only

For case 2, configure.cxx_stdlib should not be changed, which is what happened in ​a recent commit.

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

In 13ef5adf8b1a9b527beaeab10d3139bc3ce0b0fb/macports-ports (master):

compilers PG: don't set c++ stdlib for Fortran GCC

Fixes #59329