[Bug c++/29266] New: Rule that binding rvalue to a refernce need a copy ctor don't work

yuanfei8077 at gmail dot com gcc-bugzilla@gcc.gnu.org
Thu Sep 28 09:47:00 GMT 2006


Hi,

I used to open a issue at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29261 and
it's closed as no a bug.  Also it says that to bind an rvalue to a reference,
we need to let copy ctor of the class be accessible.  However, I found that
this is not the case when the invokcation is happen in intialization list.

See below reproduction code and error message.
Env:
=====
G++ 4.1
No compile option is used

Source code:
==============

using std::cout;
using std::endl;


class MemPool {
public:
       MemPool(){};
protected:
       MemPool(const MemPool& mempool);

};

template <class Type> class MemAllocator{

public:
       MemAllocator(MemPool& pool):m_pool(pool){}
       MemPool& get_pool() const {
               return m_pool;
       }
       template<class OtherType>
       MemAllocator<Type>& operator=(const MemAllocator<OtherType>& rhs){
               m_pool = rhs.get_pool();
               return *this;
       }
       MemAllocator& operator=(const MemAllocator& rhs){
               m_pool = rhs.get_pool();
               return *this;
       }

   MemAllocator(const MemAllocator& other)
       : m_pool(other.m_pool) {}
   template<class OtherType>
   MemAllocator(const MemAllocator<OtherType>& other)
       : m_pool(other.get_pool()) {}

private:
       MemAllocator();
//      MemAllocator(const MemAllocator&);
       MemPool &m_pool;

};


template <class _AllocType> class tdat_hash_map {
public:
       typedef _AllocType _Alloc;

       static void func(const _Alloc&) {};

       _Alloc malloc;
private:
       tdat_hash_map();
};
class CacheManager {
public:

       typedef tdat_hash_map<MemAllocator<int> > Map;

       Map caches;
       MemPool pool;
       CacheManager():caches(MemAllocator<int>(pool)){};

};

Error message:
==============
main.cpp: In constructor CacheManager::CacheManager()
main.cpp:56: error: no matching function for call to

tdat_hash_map<MemAllocator<int>

>::tdat_hash_map(MemAllocator<int>)main.cpp:49: note: candidates are:
tdat_hash_map<_AllocType>::tdat_hash_map() [with _AllocType =
MemAllocator<int>]
main.cpp:42: note:                 tdat_hash_map<MemAllocator<int>
>::tdat_hash_map(const tdat_hash_map<MemAllocator<int> >&)


-- 
           Summary: Rule that binding rvalue to a refernce need a copy ctor
                    don't work
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: yuanfei8077 at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29266



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