https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86513
Bug ID: 86513 Summary: ostringstream default constructor missing from libstdc++ Product: gcc Version: 9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: csaba_22 at yahoo dot co.uk Target Milestone: --- $ svn info ../trunk/ Path: ~/wk/GCC99/trunk Working Copy Root Path: ~/wk/GCC99/trunk URL: https://gcc.gnu.org/svn/gcc/trunk Relative URL: ^/trunk Repository Root: https://gcc.gnu.org/svn/gcc Repository UUID: 138bc75d-0d04-0410-961f-82ee72b054a4 Revision: 262551 Node Kind: directory Schedule: normal Last Changed Author: rguenth Last Changed Rev: 262551 Last Changed Date: 2018-07-11 09:08:54 +0200 (Wed, 11 Jul 2018) After building and running 'make install' $ g++-99 -v Using built-in specs. COLLECT_GCC=g++-99 COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../trunk/configure --program-suffix=-99 --enable-version-specific-runtime-libs --enable-languages=c,c++,lto : (reconfigured) ../trunk/configure --program-suffix=-99 --enable-version-specific-runtime-libs --enable-languages=c,c++,lto --no-create --no-recursion Thread model: posix gcc version 9.0.0 20180711 (experimental) (GCC) $ echo _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev@PLT | c++filt std::__cxx11::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::basic_ostringstream()@PLT $ $ nm /usr/local/lib/gcc/x86_64-pc-linux-gnu/9.0.0/libstdc++.so | grep _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev@PLT (no output) $ nm /usr/local/lib/gcc/x86_64-pc-linux-gnu/9.0.0/libstdc++.a | grep _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev@PLT (no output) $ nm /usr/local/lib/gcc/x86_64-pc-linux-gnu/9.0.0/libstdc++.a | grep _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1E 0000000000000000 W _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1EOS4_ 0000000000000000 W _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1ERKNS_12basic_stringIcS2_S3_EESt13_Ios_Openmode 0000000000000000 W _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1ESt13_Ios_Openmode GCC is currently unusable for any program trying to use ostringstream: I get a bunch of undefined reference to `std::__cxx11::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::basic_ostringstream()' errors.