The bare-bones minimal example:
#include <boost/iostreams/filtering_stream.hpp>
#include <boost/iostreams/filter/bzip2.hpp>
int main() {
boost::iostreams::filtering_istream in;
in.push(boost::iostreams::bzip2_compressor());
return 0;
}
Compiles fine on my machine with:
g++ -lboost_iostreams simple.cpp
But fails when c++0x is included in either instance of :
g++ -lboost_iostreams simple.cpp -std=c++0x
g++ -lboost_iostreams simple.cpp -std=gnu++0x
The insanely long error message is below. What in the code is causing c++0x to fail? How can this be fixed? I've run this three machines, each with different configurations - it fails on two, but runs correctly on a stock Ubuntu install.
In file included from /usr/local/include/boost/iostreams/traits.hpp:31:0,
from /usr/local/include/boost/iostreams/pipeline.hpp:18,
from /usr/local/include/boost/iostreams/detail/push.hpp:22,
from /usr/local/include/boost/iostreams/filtering_stream.hpp:19,
from simple.cpp:1:
/usr/local/include/boost/iostreams/detail/wrap_unwrap.hpp: In instantiation of ‘T boost::iostreams::detail::wrap(const T&, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’:
/usr/local/include/boost/iostreams/stream_buffer.hpp:94:5: required from ‘boost::iostreams::stream_buffer<T, Tr, Alloc, Mode>::stream_buffer(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:257:60: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:216:1: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push(const T&, std::streamsize, std::streamsize, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’
/usr/local/include/boost/iostreams/chain.hpp:496:7: required from ‘void boost::iostreams::detail::chain_client<Chain>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Chain = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:484:1: required from ‘void boost::iostreams::detail::chain_client<Chain>::push(const T&, std::streamsize, std::streamsize, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; Chain = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; std::streamsize = long int; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’
simple.cpp:6:47: required from here
/usr/local/include/boost/iostreams/detail/wrap_unwrap.hpp:53:14: error: use of deleted function ‘boost::iostreams::basic_bzip2_compressor<>::basic_bzip2_compressor(const boost::iostreams::basic_bzip2_compressor<>&)’
In file included from simple.cpp:2:0:
/usr/local/include/boost/iostreams/filter/bzip2.hpp:239:8: note: ‘boost::iostreams::basic_bzip2_compressor<>::basic_bzip2_compressor(const boost::iostreams::basic_bzip2_compressor<>&)’ is implicitly deleted because the default definition would be ill-formed:
/usr/local/include/boost/iostreams/filter/bzip2.hpp:239:8: error: use of deleted function ‘boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::symmetric_filter(const boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >&)’
In file included from /usr/local/include/boost/iostreams/filter/bzip2.hpp:29:0,
from simple.cpp:2:
/usr/local/include/boost/iostreams/filter/symmetric.hpp:72:7: note: ‘boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::symmetric_filter(const boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >&)’ is implicitly deleted because the default definition would be ill-formed:
/usr/local/include/boost/iostreams/filter/symmetric.hpp:72:7: error: use of deleted function ‘boost::shared_ptr<boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::impl>::shared_ptr(const boost::shared_ptr<boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::impl>&)’
In file included from /usr/local/include/boost/shared_ptr.hpp:17:0,
from /usr/local/include/boost/iostreams/chain.hpp:37,
from /usr/local/include/boost/iostreams/filtering_streambuf.hpp:17,
from /usr/local/include/boost/iostreams/filtering_stream.hpp:22,
from simple.cpp:1:
/usr/local/include/boost/smart_ptr/shared_ptr.hpp:168:25: note: ‘boost::shared_ptr<boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::impl>::shared_ptr(const boost::shared_ptr<boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::impl>&)’ is implicitly declared as deleted because ‘boost::shared_ptr<boost::iostreams::symmetric_filter<boost::iostreams::detail::bzip2_compressor_impl<std::allocator<char> >, std::allocator<char> >::impl>’ declares a move constructor or move assignment operator
In file included from /usr/local/include/boost/iostreams/detail/streambuf/indirect_streambuf.hpp:23:0,
from /usr/local/include/boost/iostreams/stream_buffer.hpp:22,
from /usr/local/include/boost/iostreams/chain.hpp:35,
from /usr/local/include/boost/iostreams/filtering_streambuf.hpp:17,
from /usr/local/include/boost/iostreams/filtering_stream.hpp:22,
from simple.cpp:1:
/usr/local/include/boost/iostreams/detail/adapter/concept_adapter.hpp: In instantiation of ‘boost::iostreams::detail::concept_adapter<T>::concept_adapter(const T&) [with T = boost::iostreams::basic_bzip2_compressor<>]’:
/usr/local/include/boost/iostreams/detail/streambuf/indirect_streambuf.hpp:187:5: required from ‘void boost::iostreams::detail::indirect_streambuf<T, Tr, Alloc, Mode>::open(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/stream_buffer.hpp:106:13: required from ‘void boost::iostreams::stream_buffer<T, Tr, Alloc, Mode>::open_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/stream_buffer.hpp:94:5: required from ‘boost::iostreams::stream_buffer<T, Tr, Alloc, Mode>::stream_buffer(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:257:60: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:216:1: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push(const T&, std::streamsize, std::streamsize, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’
/usr/local/include/boost/iostreams/chain.hpp:496:7: required from ‘void boost::iostreams::detail::chain_client<Chain>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Chain = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:484:1: required from ‘void boost::iostreams::detail::chain_client<Chain>::push(const T&, std::streamsize, std::streamsize, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; Chain = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; std::streamsize = long int; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’
simple.cpp:6:47: required from here
/usr/local/include/boost/iostreams/detail/adapter/concept_adapter.hpp:67:48: error: use of deleted function ‘boost::iostreams::basic_bzip2_compressor<>::basic_bzip2_compressor(const boost::iostreams::basic_bzip2_compressor<>&)’
In file included from /usr/local/include/boost/iostreams/detail/streambuf/direct_streambuf.hpp:26:0,
from /usr/local/include/boost/iostreams/stream_buffer.hpp:21,
from /usr/local/include/boost/iostreams/chain.hpp:35,
from /usr/local/include/boost/iostreams/filtering_streambuf.hpp:17,
from /usr/local/include/boost/iostreams/filtering_stream.hpp:22,
from simple.cpp:1:
/usr/local/include/boost/iostreams/detail/optional.hpp: In instantiation of ‘void boost::iostreams::detail::optional<T>::reset(const T&) [with T = boost::iostreams::detail::concept_adapter<boost::iostreams::basic_bzip2_compressor<> >]’:
/usr/local/include/boost/iostreams/detail/streambuf/indirect_streambuf.hpp:187:5: required from ‘void boost::iostreams::detail::indirect_streambuf<T, Tr, Alloc, Mode>::open(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/stream_buffer.hpp:106:13: required from ‘void boost::iostreams::stream_buffer<T, Tr, Alloc, Mode>::open_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/stream_buffer.hpp:94:5: required from ‘boost::iostreams::stream_buffer<T, Tr, Alloc, Mode>::stream_buffer(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:257:60: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:216:1: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push(const T&, std::streamsize, std::streamsize, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’
/usr/local/include/boost/iostreams/chain.hpp:496:7: required from ‘void boost::iostreams::detail::chain_client<Chain>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Chain = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:484:1: required from ‘void boost::iostreams::detail::chain_client<Chain>::push(const T&, std::streamsize, std::streamsize, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; Chain = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; std::streamsize = long int; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’
simple.cpp:6:47: required from here
/usr/local/include/boost/iostreams/detail/optional.hpp:100:9: error: use of deleted function ‘boost::iostreams::detail::concept_adapter<boost::iostreams::basic_bzip2_compressor<> >::concept_adapter(const boost::iostreams::detail::concept_adapter<boost::iostreams::basic_bzip2_compressor<> >&)’
In file included from /usr/local/include/boost/iostreams/detail/streambuf/indirect_streambuf.hpp:23:0,
from /usr/local/include/boost/iostreams/stream_buffer.hpp:22,
from /usr/local/include/boost/iostreams/chain.hpp:35,
from /usr/local/include/boost/iostreams/filtering_streambuf.hpp:17,
from /usr/local/include/boost/iostreams/filtering_stream.hpp:22,
from simple.cpp:1:
/usr/local/include/boost/iostreams/detail/adapter/concept_adapter.hpp:38:7: note: ‘boost::iostreams::detail::concept_adapter<boost::iostreams::basic_bzip2_compressor<> >::concept_adapter(const boost::iostreams::detail::concept_adapter<boost::iostreams::basic_bzip2_compressor<> >&)’ is implicitly deleted because the default definition would be ill-formed:
/usr/local/include/boost/iostreams/detail/adapter/concept_adapter.hpp:38:7: error: use of deleted function ‘boost::iostreams::basic_bzip2_compressor<>::basic_bzip2_compressor(const boost::iostreams::basic_bzip2_compressor<>&)’
In file included from /usr/local/include/boost/iostreams/traits.hpp:31:0,
from /usr/local/include/boost/iostreams/pipeline.hpp:18,
from /usr/local/include/boost/iostreams/detail/push.hpp:22,
from /usr/local/include/boost/iostreams/filtering_stream.hpp:19,
from simple.cpp:1:
/usr/local/include/boost/iostreams/detail/wrap_unwrap.hpp: In instantiation of ‘T boost::iostreams::detail::wrap(const T&, typename boost::disable_if<boost::iostreams::is_std_io<T> >::type*) [with T = boost::iostreams::basic_bzip2_compressor<>; typename boost::disable_if<boost::iostreams::is_std_io<T> >::type = void]’:
/usr/local/include/boost/iostreams/stream_buffer.hpp:94:5: required from ‘boost::iostreams::stream_buffer<T, Tr, Alloc, Mode>::stream_buffer(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
/usr/local/include/boost/iostreams/chain.hpp:257:60: required from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push_impl(const T&, std::streamsize, std::streamsize) [with T = boost::iostreams::basic_bzip2_compressor<>; Self = boost::iostreams::chain<boost::iostreams::input, char, std::char_traits<char>, std::allocator<char> >; Ch = char; Tr = std::char_traits<char>; Alloc = std::allocator<char>; Mode = boost::iostreams::input; std::streamsize = long int]’
Code compiled with -std=c++0x is not going to be ABI compatible with code compiled without -std=c++0x. You'll need to build Boost yourself with -std=c++0x enabled; this can be done by passing the cxxflags argument to bjam/b2.
Related
I'm trying to compile the following code (this is a minimal example), but I get a warning I can't figure out:
#include <string>
#include <variant>
#include <vector>
struct Bar {
std::wstring x = L"";
};
Bar Foo() {
std::variant<std::vector<int>, Bar> tmp = Bar();
if (std::holds_alternative<Bar>(tmp)) return std::move(std::get<Bar>(tmp));
return Bar();
}
I'm trying to build this with g++ -std=c++20 -Wall -Wextra -O2 /tmp/test.cc -c
I get the following warning:
In file included from /usr/include/x86_64-linux-gnu/c++/12/bits/c++allocator.h:33,
from /usr/include/c++/12/bits/allocator.h:46,
from /usr/include/c++/12/string:41,
from /tmp/test.cc:1:
In member function ‘void std::__new_allocator<_Tp>::deallocate(_Tp*, size_type) [with _Tp = int]’,
inlined from ‘constexpr void std::allocator< <template-parameter-1-1> >::deallocate(_Tp*, std::size_t) [with _Tp = int]’ at /usr/include/c++/12/bits/allocator.h:200:35,
inlined from ‘static constexpr void std::allocator_traits<std::allocator<_CharT> >::deallocate(allocator_type&, pointer, size_type) [with _Tp = int]’ at /usr/include/c++/12/bits/alloc_traits.h:496:23,
inlined from ‘constexpr void std::_Vector_base<_Tp, _Alloc>::_M_deallocate(pointer, std::size_t) [with _Tp = int; _Alloc = std::allocator<int>]’ at /usr/include/c++/12/bits/stl_vector.h:387:19,
inlined from ‘constexpr std::_Vector_base<_Tp, _Alloc>::~_Vector_base() [with _Tp = int; _Alloc = std::allocator<int>]’ at /usr/include/c++/12/bits/stl_vector.h:366:15,
inlined from ‘constexpr std::vector<_Tp, _Alloc>::~vector() [with _Tp = int; _Alloc = std::allocator<int>]’ at /usr/include/c++/12/bits/stl_vector.h:733:7,
inlined from ‘constexpr void std::destroy_at(_Tp*) [with _Tp = vector<int>]’ at /usr/include/c++/12/bits/stl_construct.h:88:18,
inlined from ‘constexpr void std::_Destroy(_Tp*) [with _Tp = vector<int>]’ at /usr/include/c++/12/bits/stl_construct.h:149:22,
inlined from ‘std::__detail::__variant::_Variant_storage<false, std::vector<int, std::allocator<int> >, Bar>::_M_reset()::<lambda(auto:11&&)> mutable [with auto:11 = std::vector<int>&]’ at /usr/include/c++/12/variant:472:19,
inlined from ‘constexpr _Res std::__invoke_impl(__invoke_other, _Fn&&, _Args&& ...) [with _Res = void; _Fn = __detail::__variant::_Variant_storage<false, vector<int, allocator<int> >, Bar>::_M_reset()::<lambda(auto:11&&)>; _Args = {vector<int, allocator<int> >&}]’ at /usr/include/c++/12/bits/invoke.h:61:36,
inlined from ‘constexpr std::enable_if_t<is_invocable_r_v<_Res, _Callable, _Args ...>, _Res> std::__invoke_r(_Callable&&, _Args&& ...) [with _Res = void; _Callable = __detail::__variant::_Variant_storage<false, vector<int, allocator<int> >, Bar>::_M_reset()::<lambda(auto:11&&)>; _Args = {vector<int, allocator<int> >&}]’ at /usr/include/c++/12/bits/invoke.h:111:28,
inlined from ‘static constexpr decltype(auto) std::__detail::__variant::__gen_vtable_impl<std::__detail::__variant::_Multi_array<_Result_type (*)(_Visitor, _Variants ...)>, std::integer_sequence<long unsigned int, __indices ...> >::__visit_invoke(_Visitor&&, _Variants ...) [with _Result_type = void; _Visitor = std::__detail::__variant::_Variant_storage<false, std::vector<int, std::allocator<int> >, Bar>::_M_reset()::<lambda(auto:11&&)>&&; _Variants = {std::variant<std::vector<int, std::allocator<int> >, Bar>&}; long unsigned int ...__indices = {0}]’ at /usr/include/c++/12/variant:1035:40,
inlined from ‘constexpr decltype(auto) std::__do_visit(_Visitor&&, _Variants&& ...) [with _Result_type = void; _Visitor = __detail::__variant::_Variant_storage<false, vector<int, allocator<int> >, Bar>::_M_reset()::<lambda(auto:11&&)>; _Variants = {variant<vector<int, allocator<int> >, Bar>&}]’ at /usr/include/c++/12/variant:1783:5,
inlined from ‘constexpr void std::__detail::__variant::_Variant_storage<false, _Types ...>::_M_reset() [with _Types = {std::vector<int, std::allocator<int> >, Bar}]’ at /usr/include/c++/12/variant:470:23,
inlined from ‘constexpr std::__detail::__variant::_Variant_storage<false, _Types ...>::~_Variant_storage() [with _Types = {std::vector<int, std::allocator<int> >, Bar}]’ at /usr/include/c++/12/variant:480:17,
inlined from ‘constexpr std::__detail::__variant::_Copy_ctor_base<false, std::vector<int, std::allocator<int> >, Bar>::~_Copy_ctor_base()’ at /usr/include/c++/12/variant:554:12,
inlined from ‘constexpr std::__detail::__variant::_Move_ctor_base<false, std::vector<int, std::allocator<int> >, Bar>::~_Move_ctor_base()’ at /usr/include/c++/12/variant:591:12,
inlined from ‘constexpr std::__detail::__variant::_Copy_assign_base<false, std::vector<int, std::allocator<int> >, Bar>::~_Copy_assign_base()’ at /usr/include/c++/12/variant:629:12,
inlined from ‘constexpr std::__detail::__variant::_Move_assign_base<false, std::vector<int, std::allocator<int> >, Bar>::~_Move_assign_base()’ at /usr/include/c++/12/variant:681:12,
inlined from ‘constexpr std::__detail::__variant::_Variant_base<std::vector<int, std::allocator<int> >, Bar>::~_Variant_base()’ at /usr/include/c++/12/variant:735:12,
inlined from ‘constexpr std::variant<_Types>::~variant() [with _Types = {std::vector<int, std::allocator<int> >, Bar}]’ at /usr/include/c++/12/variant:1407:28,
inlined from ‘Bar Foo()’ at /tmp/test.cc:13:1:
/usr/include/c++/12/bits/new_allocator.h:158:33: warning: ‘void operator delete(void*, std::size_t)’ called on unallocated object ‘tmp’ [-Wfree-nonheap-object]
158 | _GLIBCXX_OPERATOR_DELETE(_GLIBCXX_SIZED_DEALLOC(__p, __n));
| ^
/tmp/test.cc: In function ‘Bar Foo()’:
/tmp/test.cc:10:39: note: declared here
10 | std::variant<std::vector<int>, Bar> tmp = Bar();
| ^~~
g++ --version says g++ (Debian 12.2.0-10) 12.2.0
I know this code, as is, doesn't make that much sense; but it also shouldn't have this problem: this is a minimal example that exhibits this warning, of a much more complex function.
Strangely, the warning disappears if I do any of the following:
Change Bar::x to be a std::string.
Change tmp to be std::variant<int, Bar> (rather than having a std::vector<int> as the first type).
Remove g++ command-line flag -O2 (i.e., compile with g++ -std=c++20 -Wall -Wextra -O2 /tmp/test.cc -c).
Why would any of these changes make the warning go away!?
If I build this with --std=c++17, the problem remains.
The -Wfree-nonheap-object flag of gcc has a series of false positives bugs, among which bug 99098 is used to record these meta-bugs.
The bug in your example is similar to bug 108088 and has been listed, which issues a false positive warning message since gcc-12.
I'm working with the Eigen linear algebra library and need a vector of BiCGSTAB-solvers. Unfortunately, extending this vector is extremely difficult. The minimal (not) working example is
#include <Eigen/Eigen>
int main() {
std::vector< Eigen::BiCGSTAB< Eigen::SparseMatrix< double > > > tmp;
tmp.emplace_back();
}
and yields the error message
$ g++ -I/usr/include/eigen3 main.cpp
In file included from /usr/include/c++/12.2.0/vector:63,
from /usr/include/c++/12.2.0/functional:62,
from /usr/include/eigen3/Eigen/Core:85,
from /usr/include/eigen3/Eigen/Dense:1,
from /usr/include/eigen3/Eigen/Eigen:1,
from main.cpp:1:
/usr/include/c++/12.2.0/bits/stl_uninitialized.h: In instantiation of ‘constexpr bool std::__check_constructible() [with _ValueType = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&&]’:
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:182:4: required from ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = move_iterator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*>; _ForwardIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*]’
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:372:37: required from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, allocator<_Tp>&) [with _InputIterator = move_iterator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*>; _ForwardIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >]’
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:397:2: required from ‘_ForwardIterator std::__uninitialized_move_if_noexcept_a(_InputIterator, _InputIterator, _ForwardIterator, _Allocator&) [with _InputIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*; _ForwardIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*; _Allocator = allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >]’
/usr/include/c++/12.2.0/bits/vector.tcc:487:3: required from ‘void std::vector<_Tp, _Alloc>::_M_realloc_insert(iterator, _Args&& ...) [with _Args = {}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; iterator = std::vector<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >::iterator]’
/usr/include/c++/12.2.0/bits/vector.tcc:123:21: required from ‘std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; reference = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&]’
main.cpp:5:21: required from here
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:90:56: error: static assertion failed: result type must be constructible from input type
90 | static_assert(is_constructible<_ValueType, _Tp>::value,
| ^~~~~
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:90:56: note: ‘std::integral_constant<bool, false>::value’ evaluates to false
Trying to std::move is worse, i.e.
#include <Eigen/Eigen>
#include <utility>
int main() {
std::vector< Eigen::BiCGSTAB< Eigen::SparseMatrix< double > > > tmp;
Eigen::BiCGSTAB< Eigen::SparseMatrix< double > > solver;
tmp.push_back( std::move( solver ) );
}
leads to the error message
g++ -I/usr/include/eigen3 main.cpp
In file included from /usr/include/c++/12.2.0/x86_64-pc-linux-gnu/bits/c++allocator.h:33,
from /usr/include/c++/12.2.0/bits/allocator.h:46,
from /usr/include/c++/12.2.0/string:41,
from /usr/include/c++/12.2.0/bits/locale_classes.h:40,
from /usr/include/c++/12.2.0/bits/ios_base.h:41,
from /usr/include/c++/12.2.0/ios:42,
from /usr/include/c++/12.2.0/istream:38,
from /usr/include/c++/12.2.0/sstream:38,
from /usr/include/c++/12.2.0/complex:45,
from /usr/include/eigen3/Eigen/Core:50,
from /usr/include/eigen3/Eigen/Dense:1,
from /usr/include/eigen3/Eigen/Eigen:1,
from main.cpp:1:
/usr/include/c++/12.2.0/bits/new_allocator.h: In instantiation of ‘void std::__new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Args = {Eigen::BiCGSTAB<Eigen::SparseMatrix<double, 0, int>, Eigen::DiagonalPreconditioner<double> >}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >]’:
/usr/include/c++/12.2.0/bits/alloc_traits.h:516:17: required from ‘static void std::allocator_traits<std::allocator<_CharT> >::construct(allocator_type&, _Up*, _Args&& ...) [with _Up = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Args = {Eigen::BiCGSTAB<Eigen::SparseMatrix<double, 0, int>, Eigen::DiagonalPreconditioner<double> >}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; allocator_type = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >]’
/usr/include/c++/12.2.0/bits/vector.tcc:117:30: required from ‘std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {Eigen::BiCGSTAB<Eigen::SparseMatrix<double, 0, int>, Eigen::DiagonalPreconditioner<double> >}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; reference = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&]’
/usr/include/c++/12.2.0/bits/stl_vector.h:1294:21: required from ‘void std::vector<_Tp, _Alloc>::push_back(value_type&&) [with _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; value_type = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >]’
main.cpp:9:18: required from here
/usr/include/c++/12.2.0/bits/new_allocator.h:175:11: error: use of deleted function ‘Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >::BiCGSTAB(const Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&)’
175 | { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/eigen3/Eigen/IterativeLinearSolvers:42,
from /usr/include/eigen3/Eigen/Sparse:31,
from /usr/include/eigen3/Eigen/Eigen:2:
/usr/include/eigen3/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h:158:7: note: ‘Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >::BiCGSTAB(const Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&)’ is implicitly deleted because the default definition would be ill-formed:
158 | class BiCGSTAB : public IterativeSolverBase<BiCGSTAB<_MatrixType,_Preconditioner> >
| ^~~~~~~~
/usr/include/eigen3/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h:158:7: error: use of deleted function ‘Eigen::IterativeSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >::IterativeSolverBase(const Eigen::IterativeSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >&)’
In file included from /usr/include/eigen3/Eigen/IterativeLinearSolvers:38:
/usr/include/eigen3/Eigen/src/IterativeLinearSolvers/IterativeSolverBase.h:143:7: note: ‘Eigen::IterativeSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >::IterativeSolverBase(const Eigen::IterativeSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >&)’ is implicitly deleted because the default definition would be ill-formed:
143 | class IterativeSolverBase : public SparseSolverBase<Derived>
| ^~~~~~~~~~~~~~~~~~~
/usr/include/eigen3/Eigen/src/IterativeLinearSolvers/IterativeSolverBase.h:143:7: error: use of deleted function ‘Eigen::SparseSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >::SparseSolverBase(const Eigen::SparseSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >&)’
In file included from /usr/include/eigen3/Eigen/SparseCore:64,
from /usr/include/eigen3/Eigen/Sparse:26:
/usr/include/eigen3/Eigen/src/SparseCore/SparseSolverBase.h:67:7: note: ‘Eigen::SparseSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >::SparseSolverBase(const Eigen::SparseSolverBase<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >&)’ is implicitly deleted because the default definition would be ill-formed:
67 | class SparseSolverBase : internal::noncopyable
| ^~~~~~~~~~~~~~~~
/usr/include/eigen3/Eigen/src/SparseCore/SparseSolverBase.h:67:7: error: ‘Eigen::internal::noncopyable::noncopyable(const Eigen::internal::noncopyable&)’ is private within this context
In file included from /usr/include/eigen3/Eigen/Core:162:
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:424:21: note: declared private here
424 | EIGEN_DEVICE_FUNC noncopyable(const noncopyable&);
| ^~~~~~~~~~~
In file included from /usr/include/c++/12.2.0/vector:63,
from /usr/include/c++/12.2.0/functional:62,
from /usr/include/eigen3/Eigen/Core:85:
/usr/include/c++/12.2.0/bits/stl_uninitialized.h: In instantiation of ‘constexpr bool std::__check_constructible() [with _ValueType = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&&]’:
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:182:4: required from ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = move_iterator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*>; _ForwardIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*]’
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:372:37: required from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, allocator<_Tp>&) [with _InputIterator = move_iterator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*>; _ForwardIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >]’
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:397:2: required from ‘_ForwardIterator std::__uninitialized_move_if_noexcept_a(_InputIterator, _InputIterator, _ForwardIterator, _Allocator&) [with _InputIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*; _ForwardIterator = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >*; _Allocator = allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >]’
/usr/include/c++/12.2.0/bits/vector.tcc:487:3: required from ‘void std::vector<_Tp, _Alloc>::_M_realloc_insert(iterator, _Args&& ...) [with _Args = {Eigen::BiCGSTAB<Eigen::SparseMatrix<double, 0, int>, Eigen::DiagonalPreconditioner<double> >}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; iterator = std::vector<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >::iterator]’
/usr/include/c++/12.2.0/bits/vector.tcc:123:21: required from ‘std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {Eigen::BiCGSTAB<Eigen::SparseMatrix<double, 0, int>, Eigen::DiagonalPreconditioner<double> >}; _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; reference = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >&]’
/usr/include/c++/12.2.0/bits/stl_vector.h:1294:21: required from ‘void std::vector<_Tp, _Alloc>::push_back(value_type&&) [with _Tp = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >; _Alloc = std::allocator<Eigen::BiCGSTAB<Eigen::SparseMatrix<double> > >; value_type = Eigen::BiCGSTAB<Eigen::SparseMatrix<double> >]’
main.cpp:9:18: required from here
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:90:56: error: static assertion failed: result type must be constructible from input type
90 | static_assert(is_constructible<_ValueType, _Tp>::value,
| ^~~~~
/usr/include/c++/12.2.0/bits/stl_uninitialized.h:90:56: note: ‘std::integral_constant<bool, false>::value’ evaluates to false
I'm using Eigen 3.4 and g++ version 12.2.
Any ideas how to fix this?
Turning my comments into a proper answer:
After looking at the code, I found that BiCGSTAB like all solvers inherits from a base class designed to prevent copying, and by extension moving, too: class SparseSolverBase : internal::noncopyable
The exact reasons for this design choice I cannot tell. If I had to guess, I'd say some solvers probably use self-referential attributes (holding pointers to other members) which would break especially with fixed-size matrices. Or using Eigen::Map may cause issues on copy, especially copy-assignment.
std::vector only works with moveable types as it needs to move when it reallocates. Even when calling reserve() beforehand, the code still needs to compile, even if it is never executed.
Three workarounds come to mind:
Use std::deque. It provides a superset of all methods that vector has but its implementation means that as long as you only call emplace_back or emplace_front and not e.g. insert, it does not need moveable types. The downside is that it is a bit slower on all individual accesses
Use std::vector<std::unique_ptr<Solver>>. Less efficient than the deque but now you can also insert, reshuffle, etc.
Use std::unique_ptr<Solver[]> and use the good old new Solver[count] allocation. Starting with C++14, you can use std::make_unique<Solver[]>(count). This has the least overhead, even less than vector but the interface isn't as nice (you can use the [index] operator but the pointer doesn't even know the array size) and the number is fixed after allocation
Let the code speak it:
auto SetCompare = [](const string& a, const string& b)
{
size_t L = a.length();
size_t R = b.length();
if (L == R) return (a < b);
return L < R;
};
using MySet = std::set<string, decltype(SetCompare)>;
unordered_map<string, MySet> Map;
The insertion or access won't work:
Map["abc"];
Map["xyz"].insert("mapped to xyz");
// Insert TO set works
MySet mySet(SetCompare); // HINT
mySet.insert("x");
mySet.insert("abc");
// But not to the map!
Map.insert({"pqr", mySet});
At the HINTed location, I pass SetCompare lambda (not just type) to MySet's constructor. The question is how to pass it to the "Value" type of unordered_map?
EDIT (Compiler errors):
GCC C++17
In file included from /usr/include/c++/7/set:60:0,
from main.cpp:10:
/usr/include/c++/7/bits/stl_tree.h: In instantiation of ‘std::_Rb_tree_key_compare<_Key_compare>::_Rb_tree_key_compare() [with _Key_compare = main()::<lambda(const string&, const string&)>]’:
/usr/include/c++/7/bits/stl_tree.h:688:4: required from ‘std::pair<_T1, _T2>::pair(std::tuple<_Args1 ...>&, std::tuple<_Args2 ...>&, std::_Index_tuple<_Indexes1 ...>, std::_Index_tuple<_Indexes2 ...>) [with _Args1 = {char&&}; long unsigned int ..._Indexes1 = {0}; _Args2 = {}; long unsigned int ..._Indexes2 = {}; _T1 = const char; _T2 = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >]’
/usr/include/c++/7/tuple:1641:63: required from ‘std::pair<_T1, _T2>::pair(std::piecewise_construct_t, std::tuple<_Args1 ...>, std::tuple<_Args2 ...>) [with _Args1 = {char&&}; _Args2 = {}; _T1 = const char; _T2 = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >]’
/usr/include/c++/7/ext/new_allocator.h:136:4: required from ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; _Args = {const std::piecewise_construct_t&, std::tuple<char&&>, std::tuple<>}; _Tp = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >]’
/usr/include/c++/7/bits/alloc_traits.h:475:4: required from ‘static void std::allocator_traits<std::allocator<_CharT> >::construct(std::allocator_traits<std::allocator<_CharT> >::allocator_type&, _Up*, _Args&& ...) [with _Up = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; _Args = {const std::piecewise_construct_t&, std::tuple<char&&>, std::tuple<>}; _Tp = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; std::allocator_traits<std::allocator<_CharT> >::allocator_type = std::allocator<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > > >]’
/usr/include/c++/7/bits/hashtable_policy.h:2066:37: required from ‘std::__detail::_Hashtable_alloc<_NodeAlloc>::__node_type* std::__detail::_Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&& ...) [with _Args = {const std::piecewise_construct_t&, std::tuple<char&&>, std::tuple<>}; _NodeAlloc = std::allocator<std::__detail::_Hash_node<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >, false> >; std::__detail::_Hashtable_alloc<_NodeAlloc>::__node_type = std::__detail::_Hash_node<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >, false>]’
/usr/include/c++/7/bits/hashtable_policy.h:750:8: required from ‘std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::mapped_type& std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::operator[](std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::key_type&&) [with _Key = char; _Pair = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; _Alloc = std::allocator<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > > >; _Equal = std::equal_to<char>; _H1 = std::hash<char>; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<false, false, true>; std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::mapped_type = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >; std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::key_type = char]’
/usr/include/c++/7/bits/unordered_map.h:977:20: required from ‘std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type& std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::key_type&&) [with _Key = char; _Tp = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >; _Hash = std::hash<char>; _Pred = std::equal_to<char>; _Alloc = std::allocator<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > > >; std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >; std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::key_type = char]’
<span class="error_line" onclick="ide.gotoLine('main.cpp',31)">main.cpp:31:7</span>: required from here
/usr/include/c++/7/bits/stl_tree.h:149:24: error: use of deleted function ‘main()::::()’
: _M_key_compare()
^
main.cpp:17:24: note: a lambda closure type has a deleted default constructor
auto SetCompare = [](const string& a, const string& b)
GCC C++17
In file included from /usr/include/c++/6/set:60:0,
from main.cpp:10:
/usr/include/c++/6/bits/stl_tree.h: In instantiation of ‘std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Rb_tree_impl<_Key_compare, <anonymous> >::_Rb_tree_impl() [with _Key_compare = main()::<lambda(const string&, const string&)>; bool <anonymous> = false; _Key = std::basic_string<char>; _Val = std::basic_string<char>; _KeyOfValue = std::_Identity<std::basic_string<char> >; _Compare = main()::<lambda(const string&, const string&)>; _Alloc = std::allocator<std::basic_string<char> >]’:
/usr/include/c++/6/bits/stl_tree.h:821:18: required from ‘std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Rb_tree() [with _Key = std::basic_string<char>; _Val = std::basic_string<char>; _KeyOfValue = std::_Identity<std::basic_string<char> >; _Compare = main()::<lambda(const string&, const string&)>; _Alloc = std::allocator<std::basic_string<char> >]’
/usr/include/c++/6/bits/stl_set.h:146:14: required from ‘std::set<_Key, _Compare, _Alloc>::set() [with _Key = std::basic_string<char>; _Compare = main()::<lambda(const string&, const string&)>; _Alloc = std::allocator<std::basic_string<char> >]’
/usr/include/c++/6/tuple:1590:70: required from ‘std::pair<_T1, _T2>::pair(std::tuple<_Args1 ...>&, std::tuple<_Args2 ...>&, std::_Index_tuple<_Indexes1 ...>, std::_Index_tuple<_Indexes2 ...>) [with _Args1 = {char&&}; long unsigned int ..._Indexes1 = {0ul}; _Args2 = {}; long unsigned int ..._Indexes2 = {}; _T1 = const char; _T2 = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >]’
/usr/include/c++/6/tuple:1579:63: required from ‘std::pair<_T1, _T2>::pair(std::piecewise_construct_t, std::tuple<_Args1 ...>, std::tuple<_Args2 ...>) [with _Args1 = {char&&}; _Args2 = {}; _T1 = const char; _T2 = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >]’
/usr/include/c++/6/ext/new_allocator.h:120:4: required from ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; _Args = {const std::piecewise_construct_t&, std::tuple<char&&>, std::tuple<>}; _Tp = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >]’
/usr/include/c++/6/bits/alloc_traits.h:475:4: required from ‘static void std::allocator_traits<std::allocator<_CharT> >::construct(std::allocator_traits<std::allocator<_CharT> >::allocator_type&, _Up*, _Args&& ...) [with _Up = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; _Args = {const std::piecewise_construct_t&, std::tuple<char&&>, std::tuple<>}; _Tp = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; std::allocator_traits<std::allocator<_CharT> >::allocator_type = std::allocator<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > > >]’
/usr/include/c++/6/bits/hashtable_policy.h:1953:37: required from ‘std::__detail::_Hashtable_alloc<_NodeAlloc>::__node_type* std::__detail::_Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&& ...) [with _Args = {const std::piecewise_construct_t&, std::tuple<char&&>, std::tuple<>}; _NodeAlloc = std::allocator<std::__detail::_Hash_node<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >, false> >; std::__detail::_Hashtable_alloc<_NodeAlloc>::__node_type = std::__detail::_Hash_node<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >, false>]’
/usr/include/c++/6/bits/hashtable_policy.h:620:8: required from ‘std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::mapped_type& std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::operator[](std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::key_type&&) [with _Key = char; _Pair = std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > >; _Alloc = std::allocator<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > > >; _Equal = std::equal_to<char>; _H1 = std::hash<char>; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<false, false, true>; std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::mapped_type = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >; std::__detail::_Map_base<_Key, _Pair, _Alloc, std::__detail::_Select1st, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::key_type = char]’
/usr/include/c++/6/bits/unordered_map.h:908:20: required from ‘std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type& std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::key_type&&) [with _Key = char; _Tp = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >; _Hash = std::hash<char>; _Pred = std::equal_to<char>; _Alloc = std::allocator<std::pair<const char, std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> > > >; std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type = std::set<std::basic_string<char>, main()::<lambda(const string&, const string&)> >; std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::key_type = char]’
<span class="error_line" onclick="ide.gotoLine('main.cpp',31)">main.cpp:31:7</span>: required from here
/usr/include/c++/6/bits/stl_tree.h:602:21: error: use of deleted function ‘main()::::()’
_M_node_count(0)
^
main.cpp:17:24: note: a lambda closure type has a deleted default constructor
auto SetCompare = [](const string& a, const string& b)
^
In file included from /usr/include/c++/6/set:60:0,
from main.cpp:10:
/usr/include/c++/6/bits/stl_tree.h:628:4: warning: ‘void std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Rb_tree_impl<_Key_compare, >::_M_initialize() [with _Key_compare = main()::; bool = false; _Key = std::basic_string; _Val = std::basic_string; _KeyOfValue = std::_Identity >; _Compare = main()::; _Alloc = std::allocator >]’ used but never defined
_M_initialize()
^~~~~~~~~~~~~
VC C++14/17
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.27.29110\include\set(84,1): error C2280: 'main::<lambda_b1395bcc88464fd844969fa0764f137c>::<lambda_b1395bcc88464fd844969fa0764f137c>(void)': attempting to reference a deleted function
1>xx.cpp(923): message : see declaration of 'main::<lambda_b1395bcc88464fd844969fa0764f137c>::<lambda_b1395bcc88464fd844969fa0764f137c>'
1>xxx.cpp(923,20): message : 'main::<lambda_b1395bcc88464fd844969fa0764f137c>::<lambda_b1395bcc88464fd844969fa0764f137c>(void)': function was explicitly deleted
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.27.29110\include\set(84): message : while compiling class template member function 'std::set<std::string,main::<lambda_b1395bcc88464fd844969fa0764f137c>,std::allocator<std::string>>::set(void)'
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.27.29110\include\tuple(975): message : see reference to function template instantiation 'std::set<std::string,main::<lambda_b1395bcc88464fd844969fa0764f137c>,std::allocator<std::string>>::set(void)' being compiled
1>xxx.cpp(937): message : see reference to class template instantiation 'std::set<std::string,main::<lambda_b1395bcc88464fd844969fa0764f137c>,std::allocator<std::string>>' being compiled
Lambdas are never default constructible before C++20 (see ClosureType::ClosureType() section on cppreference), so you must pass the SetCompare variable when constructing a MySet. Using -std=c++20/-std=c++2a on clang or GCC should work (demo), as well as /std:c++latest on MSVC.
To work around this limitation in earlier C++ versions define SetCompare as a functor type:
struct SetCompare
{
bool operator()(const string& a, const string& b)
{
size_t L = a.length();
size_t R = b.length();
if (L == R) return (a < b);
return L < R;
}
};
and use this type when defining MySet
using MySet = std::set<std::string, SetCompare>;
Why does one variant assignment compile while the other does not? The template instances do not share any types and char could be converted to int, say. What is boost::variant trying to do, that it cannot do in the case of the first assignment and that it can do in the case of the second assignment? Error is below.
#include <string>
#include "boost/variant.hpp"
int main()
{
boost::variant<char> v1;
boost::variant<std::string, int, double> v2;
v1 = v2; // compile error
v2 = v1; // compiles fine
return 0;
}
In file included from /usr/include/boost/variant.hpp:17:0,
from v.cpp:3:
/usr/include/boost/variant/variant.hpp: In instantiation of 'int boost::variant<T0, TN>::convert_copy_into::internal_visit(T&, int) const [with T = const std::basic_string<char>; T0_ = char; TN = {}]':
/usr/include/boost/variant/detail/visitation_impl.hpp:113:9: required from 'typename Visitor::result_type boost::detail::variant::visitation_impl_invoke_impl(int, Visitor&, VoidPtrCV, T*, mpl_::true_) [with Visitor = boost::variant<char>::convert_copy_into; VoidPtrCV = const void*; T = std::basic_string<char>; typename Visitor::result_type = int; mpl_::true_ = mpl_::bool_<true>]'
/usr/include/boost/variant/detail/visitation_impl.hpp:156:9: required from 'typename Visitor::result_type boost::detail::variant::visitation_impl_invoke(int, Visitor&, VoidPtrCV, T*, NoBackupFlag, int) [with Visitor = boost::variant<char>::convert_copy_into; VoidPtrCV = const void*; T = std::basic_string<char>; NoBackupFlag = boost::variant<std::basic_string<char>, int, double>::has_fallback_type_; typename Visitor::result_type = int]'
/usr/include/boost/variant/detail/visitation_impl.hpp:237:5: required from 'typename Visitor::result_type boost::detail::variant::visitation_impl(int, int, Visitor&, VoidPtrCV, mpl_::false_, NoBackupFlag, Which*, step0*) [with Which = mpl_::int_<0>; step0 = boost::detail::variant::visitation_impl_step<boost::mpl::l_iter<boost::mpl::l_item<mpl_::long_<3l>, std::basic_string<char>, boost::mpl::l_item<mpl_::long_<2l>, int, boost::mpl::l_item<mpl_::long_<1l>, double, boost::mpl::l_end> > > >, boost::mpl::l_iter<boost::mpl::l_end> >; Visitor = boost::variant<char>::convert_copy_into; VoidPtrCV = const void*; NoBackupFlag = boost::variant<std::basic_string<char>, int, double>::has_fallback_type_; typename Visitor::result_type = int; mpl_::false_ = mpl_::bool_<false>]'
/usr/include/boost/variant/variant.hpp:2245:13: required from 'static typename Visitor::result_type boost::variant<T0, TN>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::variant<char>::convert_copy_into; VoidPtrCV = const void*; T0_ = std::basic_string<char>; TN = {int, double}; typename Visitor::result_type = int]'
/usr/include/boost/variant/variant.hpp:2267:13: [ skipping 2 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/usr/include/boost/variant/variant.hpp:1581:13: required from 'void boost::variant<T0, TN>::convert_construct_variant(Variant&) [with Variant = const boost::variant<std::basic_string<char>, int, double>; T0_ = char; TN = {}]'
/usr/include/boost/variant/variant.hpp:1628:42: required from 'void boost::variant<T0, TN>::convert_construct(const boost::variant<U0, UN ...>&, long int) [with U0 = std::basic_string<char>; UN = {int, double}; T0_ = char; TN = {}]'
/usr/include/boost/variant/variant.hpp:1649:38: required from 'boost::variant<T0, TN>::variant(const T&) [with T = boost::variant<std::basic_string<char>, int, double>; T0_ = char; TN = {}]'
/usr/include/boost/variant/variant.hpp:2059:29: required from 'void boost::variant<T0, TN>::assign(const T&) [with T = boost::variant<std::basic_string<char>, int, double>; T0_ = char; TN = {}]'
/usr/include/boost/variant/variant.hpp:2099:19: required from 'boost::variant<T0, TN>& boost::variant<T0, TN>::operator=(const T&) [with T = boost::variant<std::basic_string<char>, int, double>; T0_ = char; TN = {}]'
v.cpp:10:6: required from here
/usr/include/boost/variant/variant.hpp:1366:61: error: no matching function for call to 'boost::variant<char>::initializer::initialize(void* const&, const std::basic_string<char>&)'
return initializer::initialize(storage_, operand);
^
/usr/include/boost/variant/variant.hpp:1366:61: note: candidates are:
In file included from /usr/include/boost/variant/variant.hpp:32:0,
from /usr/include/boost/variant.hpp:17,
from v.cpp:3:
/usr/include/boost/variant/detail/initializer.hpp:104:24: note: static int boost::detail::variant::make_initializer_node::apply<BaseIndexPair, Iterator>::initializer_node::initialize(void*, boost::detail::variant::make_initializer_node::apply<BaseIndexPair, Iterator>::initializer_node::param_T) [with BaseIndexPair = boost::mpl::pair<boost::detail::variant::initializer_root, mpl_::int_<0> >; Iterator = boost::mpl::l_iter<boost::mpl::list1<char> >; boost::detail::variant::make_initializer_node::apply<BaseIndexPair, Iterator>::initializer_node::param_T = const char&]
static int initialize(void* dest, param_T operand)
^
/usr/include/boost/variant/detail/initializer.hpp:104:24: note: no known conversion for argument 2 from 'const std::basic_string<char>' to 'boost::detail::variant::make_initializer_node::apply<boost::mpl::pair<boost::detail::variant::initializer_root, mpl_::int_<0> >, boost::mpl::l_iter<boost::mpl::list1<char> > >::initializer_node::param_T {aka const char&}'
/usr/include/boost/variant/detail/initializer.hpp:115:24: note: static int boost::detail::variant::make_initializer_node::apply<BaseIndexPair, Iterator>::initializer_node::initialize(void*, boost::detail::variant::make_initializer_node::apply<BaseIndexPair, Iterator>::initializer_node::param2_T) [with BaseIndexPair = boost::mpl::pair<boost::detail::variant::initializer_root, mpl_::int_<0> >; Iterator = boost::mpl::l_iter<boost::mpl::list1<char> >; boost::detail::variant::make_initializer_node::apply<BaseIndexPair, Iterator>::initializer_node::param2_T = char&&]
static int initialize(void* dest, param2_T operand)
^
/usr/include/boost/variant/detail/initializer.hpp:115:24: note: no known conversion for argument 2 from 'const std::basic_string<char>' to 'boost::detail::variant::make_initializer_node::apply<boost::mpl::pair<boost::detail::variant::initializer_root, mpl_::int_<0> >, boost::mpl::l_iter<boost::mpl::list1<char> > >::initializer_node::param2_T {aka char&&}'
/usr/include/boost/variant/detail/initializer.hpp:149:17: note: static void boost::detail::variant::initializer_root::initialize()
static void initialize();
^
/usr/include/boost/variant/detail/initializer.hpp:149:17: note: candidate expects 0 arguments, 2 provided
A char definitely can be stored in an int but the converse is not always true. Therefore the one that fails to compile would be unsafe at runtime, so you're probably better off with it failing. Cast the int to a char if you must.
While trying out HippoMocks (Cygwin, GCC 4.5.3, CppUnit) to mock an interface, one of the methods is causing compilation to fail. Further triage shows that only mocking methods with std::vector as arguments would fail.
e.g.
m_Mocks.ExpectCall(m_EmpSvcMock.get(), IEmployeeServiceProxy::GetEmployees); // compile error!
m_Mocks.ExpectCall(m_EmpSvcMock.get(), IEmployeeServiceProxy::AddEmployee); // compile OK!
where
class IEmployeeServiceProxy
{
public:
virtual ~IEmployeeServiceProxy() { }
virtual void AddEmployee(const Employee&) = 0;
virtual void GetEmployees(std::vector<Employee>&) = 0;
};
struct Employee
{
boost::uuids::uuid Id;
std::string Name;
};
Compiler error:
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stream_iterator.h: In member function ‘std::ostream_iterator<_Tp, _CharT, _Traits>& std::ostream_iterator<_Tp, _CharT, _Traits>::operator=(const _Tp&) [with _Tp = EmployeeServiceLib::Employee, _CharT = char, _Traits = std::char_traits<char>, std::ostream_iterator<_Tp, _CharT, _Traits> = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’:
In file included from /usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/iterator:67:0,
from /usr/include/boost/uuid/string_generator.hpp:14,
from /usr/include/boost/uuid/uuid_generators.hpp:15,
from tests/../../RcfTestShared/IEmployeeService.hpp:7,
from tests/../IEmployeeServiceProxy.h:11,
from tests/ClientTest.h:13,
from tests/ClientTest.cpp:8:
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:349:8: instantiated from ‘static _OI std::__copy_move<false, false, std::random_access_iterator_tag>::__copy_m(_II, _II, _OI) [with _II = const EmployeeServiceLib::Employee*, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:404:70: instantiated from ‘_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false, _II = const EmployeeServiceLib::Employee*, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:442:39: instantiated from ‘_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false, _II = __gnu_cxx::__normal_iterator<const EmployeeServiceLib::Employee*, std::vector<EmployeeServiceLib::Employee> >, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stl_algobase.h:474:18: instantiated from ‘_OI std::copy(_II, _II, _OI) [with _II = __gnu_cxx::__normal_iterator<const EmployeeServiceLib::Employee*, std::vector<EmployeeServiceLib::Employee> >, _OI = std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >]’
../../RCF/RCF-1.3.1/include/RCF/Tools.hpp:116:9: instantiated from ‘std::ostream& std::operator<<(std::ostream&, const std::vector<_RealType>&) [with T = EmployeeServiceLib::Employee, std::ostream = std::basic_ostream<char>]’
../../hippomocks/HippoMocks/hippomocks.h:94:5: instantiated from ‘static void printArg<T>::print(std::ostream&, T, bool) [with T = std::vector<EmployeeServiceLib::Employee>&, std::ostream = std::basic_ostream<char>]’
../../hippomocks/HippoMocks/hippomocks.h:170:5: instantiated from ‘void ref_tuple<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P>::printTo(std::ostream&) const [with A = std::vector<EmployeeServiceLib::Employee>&, B = NullType, C = NullType, D = NullType, E = NullType, F = NullType, G = NullType, H = NullType, I = NullType, J = NullType, K = NullType, L = NullType, M = NullType, N = NullType, O = NullType, P = NullType, std::ostream = std::basic_ostream<char>]’
tests/ClientTest.cpp:47:1: instantiated from here
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/bits/stream_iterator.h:196:2: error: cannot bind ‘std::ostream_iterator<EmployeeServiceLib::Employee, char, std::char_traits<char> >::ostream_type’ lvalue to ‘std::basic_ostream<char>&&’
/usr/lib/gcc/i686-pc-cygwin/4.5.3/include/c++/ostream:579:5: error: initializing argument 1 of ‘std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&&, const _Tp&) [with _CharT = char, _Traits = std::char_traits<char>, _Tp = EmployeeServiceLib::Employee]’
Possibly it's complaining that you don't have operator<< defined for Employee, but I'm not certain. I think you've missed the last line of your error messages? In any case I would read the documentation and see what requirements they have for the class being tested.
Requiring you to define operator== and operator<< and maybe others is pretty standard for a unit testing framework. If you think about it a unit testing framework is going to need to compare objects of the types you are testing and maybe going to try and output those objects when things go wrong.