https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86977
Bug ID: 86977
Summary: [g++ 8.1.0-5ubuntu1~14.04] error: static assertion
failed: unordered container must have the same
value_type as its allocator
Product: gcc
Version: 8.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: joao at neto dot pt
Target Milestone: ---
**I'm not sure this is a bug; but I couldn't find alternate root cause. Sorry
if it's not!**
The following code can be compiled successfully in `g++-6` and `g++-7`, but not
in `g++-8`, which results in an error:
```
In file included from /usr/include/c++/8/unordered_map:46,
from /usr/include/c++/8/functional:61,
from test.cpp:3:
/usr/include/c++/8/bits/hashtable.h: In instantiation of ‘class
std::_Hashtable<int, std::pair<const int, Thing>,
boost::interprocess::allocator<void, boost::interprocess::segment_manager<char,
boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>,
boost::interprocess::iset_index> >, std::__detail::_Select1st,
std::equal_to<int>, std::hash<int>, std::__detail::_Mod_range_hashing,
std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy,
std::__detail::_Hashtable_traits<false, false, true> >’:
/usr/include/c++/8/bits/unordered_map.h:105:18: required from ‘class
std::unordered_map<int, Thing, std::hash<int>, std::equal_to<int>,
boost::interprocess::allocator<void, boost::interprocess::segment_manager<char,
boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>,
boost::interprocess::iset_index> > >’
test.cpp:30:15: required from here
/usr/include/c++/8/bits/hashtable.h:192:21: error: static assertion failed:
unordered container must have the same value_type as its allocator
static_assert(is_same<typename _Alloc::value_type, _Value>{},
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
```
#include <sys/mman.h>
#include <sys/syscall.h>
#include <functional>
#include <memory>
#include <unordered_map>
#include <string>
#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/shared_memory_object.hpp>
class Thing {
public:
volatile Thing *_parent;
explicit Thing(Thing *parent) : _parent(parent) {}
};
namespace ipc = boost::interprocess;
using Segment = ipc::managed_shared_memory;
using Manager = Segment::segment_manager;
template <typename T> using Alloc = ipc::allocator<T, Manager>;
template <typename K, typename V, typename KH = std::hash<K>, typename KEq =
std::equal_to<K>>
using HashMap = std::unordered_map<K, V, KH, KEq, Alloc<void>>;
typedef HashMap<pid_t, Thing> ThingMap;
int main() {
boost::interprocess::shared_memory_object::remove("test");
Segment my_segment{ipc::create_only, "test", 1ul<<40};
Manager *my_manager = my_segment.get_segment_manager();
ThingMap *my_map =
my_segment.find_or_construct<ThingMap>("my_map")(my_manager);
my_map->emplace(123, nullptr);
printf("Hello world\n");
return 0;
}
```
The code can be seen on GitHub, and there is a Travis build reproducing the
issue. I've posted on StackOverflow but got no replies.
https://github.com/joaomlneto/clang-tidbit
https://travis-ci.com/joaomlneto/clang-tidbit/builds/81896897
https://stackoverflow.com/questions/51858747/compilation-tidbits-on-g-clang-using-libboost-g8-compilation-fails-wh
Using `libboost 1.54` (default for `apt-get install libboost-all-dev` in Ubuntu
14.04).
Compiled with `$(CXX) -std=c++17 $^ -o $@ -pthread -ldl -rdynamic -lrt`
If I change to `-std=gnu++17`, then it works.
https://travis-ci.com/joaomlneto/clang-tidbit/builds/81897835
Below is information on the system (although is a pretty standard Ubuntu
14.04):
```
# g++-8 -v
Using built-in specs.
COLLECT_GCC=g++-8
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
8.1.0-5ubuntu1~14.04' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=gcc4-compatible --disable-libstdcxx-dual-abi
--enable-gnu-unique-object --disable-vtable-verify --enable-libmpx
--enable-plugin --with-system-zlib --with-target-system-zlib
--enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 8.1.0 (Ubuntu 8.1.0-5ubuntu1~14.04)
```
```
# uname -a
Linux d0710afa7fb5 4.15.0-30-generic #32-Ubuntu SMP Thu Jul 26 17:42:43 UTC
2018 x86_64 x86_64 x86_64 GNU/Linux
```
```
# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.5 LTS
Release: 14.04
Codename: trusty
```
