Yes, i noted. Previous PETSc's versions worked with that flag, but the 3.16.0 no longer. On 10/2/21 17:48, Stefano Zampini wrote:

The issue is that you have --with-cxxlib-autodetect=0 in your configure log, so PETSc skip appending lstdc++ to the list of libraries used to link the shared library. If you don't care, just remove the configure flag

I'm removing '-std=[c/gnu]++17' On 10/2/21 17:38, Jacob Faibussowitsch wrote:

Can you try the following?

In $PETSC_DIR/$PETSC_ARCH/lib/petsc/conf/petscvariables there are two variables, PETSC_EXTERNAL_LIB_BASIC and PETSC_WITH_EXTERNAL_LIB. Append -lstdc++ to both of them and re-run your make command with verbose output:

$ make all V=1 $ make check

P.S. There is no longer a need to set -std=[c/gnu]++17 in your own flags; configure will detect up to c++17. For gnu-ish compilers (gcc/clang) it will try to use gnu extensions — in fact if you search for ‘checkCxxDialect' in you configure.log, you’ll see it appropriately selects gnu++17.

Thank you all. -- --- Antonio Trande Fedora Project mailto: [email protected] GPG key: 0x29FBC85D7A51CC2F GPG key server: https://keyserver1.pgp.com/