Ceph

Clang complains:
/home/jenkins/workspace/ceph-master/src/tools/cephfs/MetaTool.cc:419:30: error: invalid operands to binary expression ('basic_ostream<char, std::__1::char_traits<char> >' and 'buffer::error')
<< ": " << err << std::endl;
~_~~~~ ^ ~~~
/usr/include/c++/v1/ostream:219:20: note: candidate function not viable: no known conversion from 'buffer::error' to 'const void ' for 1st argument; take the address of the argument with &
basic_ostream& operator<<(const void _p);
^
/usr/include/c++/v1/type_traits:4843:3: note: candidate function template not viable: no known conversion from 'basic_ostream<char, std::_1::char_traits<char> >' to 'std::byte' for 1st argument
operator<< (byte __lhs, _Integer __shift) noexcept
^