https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123193
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c++ |libstdc++
Last reconfirmed| |2026-06-25
Status|UNCONFIRMED |WAITING
Ever confirmed|0 |1
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Christophe Lyon from comment #0)
> Linaro CI has detected a failure in g++.dg/modules/compile-std1.C on some
> arm configurations:
> --target arm-eabi --disable-multilib --with-mode=thumb --with-cpu=cortex-m7
> --with-float=hard
>
> and
> --target arm-eabi --disable-multilib --with-mode=arm --with-arch=armv7-a
> --with-fpu=vfpv3-d16 --with-float=softfp
>
>
> The logs say:
>
> In file included from
> /arm-eabi/libstdc++-v3/include/arm-eabi/bits/stdc++.h:227:
> /arm-eabi/libstdc++-v3/include/print: In member function 'virtual void
> std::__format::_File_sink::_M_overflow()':
> /arm-eabi/libstdc++-v3/include/print:197:20: error: '::fwrite_unlocked' has
> not been declared; did you mean '_fwrite_unlocked_r'?
> /arm-eabi/libstdc++-v3/include/print: In constructor
> 'std::__format::_File_sink::_File_sink(FILE*, bool)':
> /arm-eabi/libstdc++-v3/include/print:212:9: error: '::flockfile' has not
> been declared; did you mean '_flockfile'?
> /arm-eabi/libstdc++-v3/include/print: In destructor
> 'std::__format::_File_sink::~_File_sink()':
> /arm-eabi/libstdc++-v3/include/print:218:11: error: '::putc_unlocked' has
> not been declared; did you mean '_putc_unlocked_r'?
> /arm-eabi/libstdc++-v3/include/print:219:9: error: '::funlockfile' has not
> been declared; did you mean '_funlockfile'?
> In file included from
> /arm-eabi/libstdc++-v3/include/arm-eabi/bits/stdc++.h:227,
> from /arm-eabi/libstdc++-v3/include/bits/std.cc:26:
> /arm-eabi/libstdc++-v3/include/print: In member function 'virtual void
> std::__format::_File_sink::_M_overflow()':
> /arm-eabi/libstdc++-v3/include/print:197:20: error: '::fwrite_unlocked' has
> not been declared; did you mean '_fwrite_unlocked_r'?
> /arm-eabi/libstdc++-v3/include/print: In constructor
> 'std::__format::_File_sink::_File_sink(FILE*, bool)':
> /arm-eabi/libstdc++-v3/include/print:212:9: error: '::flockfile' has not
> been declared; did you mean '_flockfile'?
> /arm-eabi/libstdc++-v3/include/print: In destructor
> 'std::__format::_File_sink::~_File_sink()':
> /arm-eabi/libstdc++-v3/include/print:218:11: error: '::putc_unlocked' has
> not been declared; did you mean '_putc_unlocked_r'?
> /arm-eabi/libstdc++-v3/include/print:219:9: error: '::funlockfile' has not
> been declared; did you mean '_funlockfile'?
All the errors above are guarded with:
#if _GLIBCXX_USE_STDIO_LOCKING && _GLIBCXX_USE_GLIBC_STDIO_EXT
which should not be true for arm-none-eabi. Even the usual "newlib declares
everything then fails at link time" problem shouldn't cause these errors. I
don't know what's happening here.
I think all the other errors should have been fixed by r16-5939-gda97de41f8837a
Is this still failing for Linaro CI?
