http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56922
Bug #: 56922
Summary: set: the default constructor should be explicit
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: akim.demai...@gmail.com
Hi all,
According to http://llvm.org/bugs/show_bug.cgi?id=15724, there is no default
constructor for set, only a constructor whose arguments are optional, but it
turns out that this constructor is explicit. So, at least according to C++98
(I don't know about C++11), the following piece of code is expected to fail.
$ cat /tmp/set.cc
#include <set>
int
main()
{
std::set<int> s = {};
}
$ g++-mp-4.8 -std=c++11 -Wall /tmp/set.cc
Clang rejects it.
$ clang++-mp-3.3 -std=c++11 -Wall /tmp/set.cc -stdlib=libc++
/tmp/set.cc:5:17: error: chosen constructor is explicit in copy-initialization
std::set<int> s = {};
^ ~~
/opt/local/libexec/llvm-3.3/bin/../lib/c++/v1/set:378:14: note: constructor
declared here
explicit set(const value_compare& __comp = value_compare())
^
1 error generated.
The actual case at hand is a function with an optional argument which is a set,
and I used "= {}", which is rejected by clang++.
Cheers!
