https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115420
Bug ID: 115420
Summary: Default constructor of unordered_map deleted
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: krebbel at gcc dot gnu.org
Target Milestone: ---
t.cc:
#include <unordered_map>
#include <condition_variable>
class Foo {
std::unordered_map<std::string, uint64_t> bar;
Foo() : bar() {}
};
g++ -std=c++11 -c t.cc
fails with:
t.cc: In constructor ‘Foo::Foo()’:
t.cc:6:11: error: use of deleted function ‘std::unordered_map<_Key, _Tp, _Hash,
_Pred, _Alloc>::unordered_map() [with _Key = std::__cxx11::basic_string<char>;
_Tp = long unsigned int; _Hash = std::hash<std::__cxx11::basic_string<char> >;
_Pred = std::equal_to<std::__cxx11::basic_string<char> >; _Alloc =
std::allocator<std::pair<const std::__cxx11::basic_string<char>, long unsigned
int> >]’
6 | Foo() : bar() {}
| ^~~~~
In file included from
/home2/andreas/bisect/gcc-02dab998665-install/include/c++/13.0.0/unordered_map:41,
from t.cc:1:
/home2/andreas/bisect/gcc-02dab998665-install/include/c++/13.0.0/bits/unordered_map.h:146:7:
note: ‘std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map()
[with _Key = std::__cxx11::basic_string<char>; _Tp = long unsigned int; _Hash =
std::hash<std::__cxx11::basic_string<char> >; _Pred =
std::equal_to<std::__cxx11::basic_string<char> >; _Alloc =
std::allocator<std::pair<const std::__cxx11::basic_string<char>, long unsigned
int> >]’ is implicitly deleted because the default definition would be
ill-formed:
146 | unordered_map() = default;
| ^~~~~~~~~~~~~
starting with:
commit 227351345d0caa596eff8325144f15b15f704c08
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Jan 12 13:03:01 2023 +0000
libstdc++: Do not include <system_error> in concurrency headers
The <condition_variable>, <mutex>, and <shared_mutex> headers use
std::errc constants, but don't use std::system_error itself. They only
use the __throw_system_error(int) function, which is defined in
<bits/functexcept.h>.
By including the header for the errc constants instead of the whole of
<system_error> we avoid depending on the whole std::string definition.
libstdc++-v3/ChangeLog:
* include/bits/std_mutex.h: Remove <system_error> include.
* include/std/condition_variable: Add <bits/error_constants.h>
include.
* include/std/mutex: Likewise.
* include/std/shared_mutex: Likewise.
The testcase works fine with gcc 12 and clang.
There are similar BZs on that topic but these do not seem to fit exactly, as I
understand it (e.g. 107022)
