http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56004
Bug #: 56004
Summary: Possible bug with decltype and access modifer order
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: david.irv...@maidsafe.net
Please see this stackoverflow question for an overview.
http://stackoverflow.com/questions/14188535/clang-access-modifier-order-and-decltype
The issue seems to be that the private members are not visible at compilation
to the decltype call. This is a minimum example (from the question). (I am the
questioner in this case). This also seems to appear as a 'bug' in gcc but not
msvc (12). I am not 100% convinced but cannot find in the standard why this
will not work. I hope this helps.
#include <future>
#include <iostream>
#include <thread>
#include <vector>
template <class T> T &self(T &t) { return t; }
template<typename T> struct Dependent { };
template<typename T>
class Synchronised : Dependent<T>{
public:
explicit Synchronised(T t = T()) : t_(t) {}
template<typename Functor>
auto operator()(Functor functor) const ->decltype(functor(self(*this).t_)) {
//auto operator()(Functor functor) const ->decltype(functor(this->t_)) {
std::lock_guard<std::mutex> lock(mutex_);
return functor(t_);
}
private:
mutable T t_;
mutable std::mutex mutex_;
};
int main() {
Synchronised<std::string> sync_string("Start\n");
std::vector<std::future<void>> futures;
}
