Description of problem: std::filesystem::_Dir_base::advance(bool, std::error_code&) not defined Version-Release number of selected component (if applicable): How reproducible: constantly reproducible. Steps to Reproduce: $ cat FindStdFilesystem_test.cc #if __has_include(<filesystem>) #include <filesystem> namespace fs = std::filesystem; #elif __has_include(<experimental/filesystem>) #include <experimental/filesystem> namespace fs = std::experimental::filesystem; #else #error std::filesystem not available! #endif int main() { fs::create_directory("sandbox"); fs::remove_all("sandbox"); } $ scl enable gcc-toolset-9 bash $ g++ -std=c++17 FindStdFilesystem_test.cc /bin/ld: a.out: hidden symbol `_ZNSt10filesystem9_Dir_base7advanceEbRSt10error_code' isn't defined /bin/ld: final link failed: Bad value collect2: error: ld returned 1 exit status Actual results: the code using std::filesystem fails to link. Expected results: the code using std::filesystem links. Additional info: $ c++filt _ZNSt10filesystem9_Dir_base7advanceEbRSt10error_code std::filesystem::_Dir_base::advance(bool, std::error_code&) $ nm -C /opt/rh/gcc-toolset-9/root/usr/lib/gcc/aarch64-redhat-linux/9/libstdc++_nonshared.a | grep _Dir_base U std::filesystem::_Dir_base::advance(bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 n std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) U std::filesystem::_Dir_base::advance(bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 n std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) $ dnf list installed gcc-toolset-9-gcc-c++ Installed Packages gcc-toolset-9-gcc-c++.aarch64 9.2.1-2.3.el8 @AppStream please note, our building host is running CentOS8, and is using GTS from AppStream. but i think this issue also applies to RHEL8. this issue is only observed on aarch64. on amd64, i have: $ nm -C /opt/rh/gcc-toolset-9/root/usr/lib/gcc/x86_64-redhat-linux/9/libstdc++_nonshared.a | grep _Dir_base 0000000000000000 W std::filesystem::_Dir_base::advance(bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 n std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::advance(bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 W std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) 0000000000000000 n std::filesystem::_Dir_base::_Dir_base(char const*, bool, std::error_code&) $ dnf list installed gcc-toolset-9-gcc-c++ Installed Packages gcc-toolset-9-gcc-c++.x86_64 9.2.1-2.3.el8 @rhel-8-for-x86_64-appstream-rpms
i filed a similar issue: https://bugzilla.redhat.com/show_bug.cgi?id=1853900 before. but a different symbol was missing in that one, and we only have this link failure on aarch64.
There indeed is a problem with that symbol in GTS 9: 308: 0000000000000000 0 NOTYPE GLOBAL HIDDEN UND _ZNSt10filesystem9_Dir_base7advanceEbRSt10error_code all of these issues were fixed in GTS 10. I suppose you can't switch to gcc-toolset-10-gcc?
Also, -std=c++17 is still experimental in GCC 9, so I'm not sure if we will be able to provide updates for it.
hi Marek, thank you for your prompt reply! regarding C++17 support on GCC-9, I was mostly referencing - https://gcc.gnu.org/projects/cxx-status.html#cxx17 - https://gcc.gnu.org/gcc-9/changes.html#libstdcxx but yeah, since we have GCC-10, there is no good reason to stick with GCC-9! I will try to contact our lab administrator to see if we can switch to RHEL8 for using GTS-10. as, FWIW, CentOS8's GTS-10 is currently broken. see https://bugs.centos.org/view.php?id=17860. I am closing this ticket as "won't fix".
(In reply to Kefu Chai from comment #4) > hi Marek, > > thank you for your prompt reply! > > regarding C++17 support on GCC-9, I was mostly referencing > > - https://gcc.gnu.org/projects/cxx-status.html#cxx17 > - https://gcc.gnu.org/gcc-9/changes.html#libstdcxx > > but yeah, since we have GCC-10, there is no good reason to stick with GCC-9! > I will try to contact our lab administrator to see if we can switch to RHEL8 > for using GTS-10. as, FWIW, CentOS8's GTS-10 is currently broken. see > https://bugs.centos.org/view.php?id=17860. > > I am closing this ticket as "won't fix". Thanks for understanding! Note that we don't really consider C++17 to be stable in GCC 9, but it is considered stable in GCC 10. So switching to GCC 10 definitely makes sense from this point of view.