Error when compiling with gcc 'undefined reference to `libint2_static_cleanup'

[HalblauterPC]

When compiling a project derived from the hartree-fock++.cc, I get error as follows.
I used version 2.7.1 of libint and gcc version 8.3.0 on Debian.

gcc -O2 -o sys-integrals sysmaker.cc -I/usr/local/libint/2.8.0/include/ -I/usr/local/include/eigen3/ -I/lib/boost/include -lm -lstdc++
/usr/bin/ld: /tmp/cc5Cax8u.o: in function 'std::unique_ptr<libint2::detail::__initializer, std::default_delete<libint2::detail::__initializer>::~unique_ptr()':
sysmaker.cc:(.text._ZNSt10unique_ptrIN7libint26detail13__initializerESt14default_deleteIS2_EED2Ev[_ZNSt10unique_ptrIN7libint26detail13__initializerESt14default_deleteIS2_EED5Ev]+0xa): undefined reference to 'libint2_static_cleanup'
/usr/bin/ld: /tmp/cc5Cax8u.o: in function 'libint2::Engine::~Engine()':
sysmaker.cc:(.text._ZN7libint26EngineD2Ev[_ZN7libint26EngineD5Ev]+0xf): undefined reference to 'libint2_cleanup_default'
/usr/bin/ld: /tmp/cc5Cax8u.o: in function 'libint2::Engine::_initialize()':
sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x30d): undefined reference to 'libint2_need_memory_default'
/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x325): undefined reference to 'libint2_init_default'
/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x32c): undefined reference to 'libint2_build_default'
/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x387): undefined reference to 'libint2_need_memory_default'

[...]

/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x226c): undefined reference to 'libint2_cleanup_default'
/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x2280): undefined reference to 'libint2_cleanup_default'
/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x2294): undefined reference to 'libint2_cleanup_default'
/usr/bin/ld: sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x22a8): undefined reference to 'libint2_cleanup_default'
/usr/bin/ld: /tmp/cc5Cax8u.o:sysmaker.cc:(.text._ZN7libint26Engine11_initializeEv[_ZN7libint26Engine11_initializeEv]+0x22bc): more undefined references to 'libint2_cleanup_default' follow
/usr/bin/ld: /tmp/cc5Cax8u.o: in function 'main':
sysmaker.cc:(.text.startup+0x2aed): undefined reference to 'libint2_static_cleanup'
/usr/bin/ld: sysmaker.cc:(.text.startup+0x2d0b): undefined reference to 'libint2_static_init'
/usr/bin/ld: sysmaker.cc:(.text.startup+0x2d23): undefined reference to 'libint2_static_cleanup'
collect2: error: ld returned 1 exit status

[loriab]

I'm not at all sure that this is your problem, but depending on where you're linking to libint from (build or install tree) and the buildsys to assemble your hf++ derived project (gnu make or cmake), you may want to try adding the compile definition __COMPILING_LIBINT2=1 as described slightly more under https://github.com/loriab/libint/blob/new-cmake-2023-take2-b/INSTALL.md#detection-time-compatibility

[HalblauterPC]

The problem were missing statements in the gcc statement:
-L /usr/local/libint/2.8.0/lib64/ -lint2
The errors complained that gcc did only find headers without the corresponding linbrary files.

so that the compile prompt is as follows:
gcc -O2 -o sys-integrals sysmaker.cc -I/usr/local/libint/2.8.0/include/ -I/usr/local/include/eigen3/ -I/lib/boost/include -lm -lstdc++ -L /usr/local/libint/2.8.0/lib64/ -lint2