[boost] problem when using boost::noncopyable_::noncopyable

From: bwlee (bwlee.sky_at_[hidden])
Date: 2006-03-29 01:06:27

I defined a class inherited from noncoyable and singleton, but when 
compiled by vc8.0(VC++ express 2005), it report a error like this:

template<typename T>
class thread_pool : boost::noncopyable, public boost::singleton
{
//...

};

center\code\project.net\include\thread_pool.hpp(227) : error C2248: 
'boost::noncopyable_::noncopyable::operator =' : cannot access private 
member declared in class 'boost::noncopyable_::noncopyable'
         c:\boost\include\boost-1_33_1\boost\noncopyable.hpp(28) : see 
declaration of 'boost::noncopyable_::noncopyable::operator ='
         c:\boost\include\boost-1_33_1\boost\noncopyable.hpp(22) : see 
declaration of 'boost::noncopyable_::noncopyable'
         This diagnostic occurred in the compiler generated function 
'core::thread_pool<worker> &core::thread_pool<worker>::operator 
=(robert::core::thread_pool<worker> &)'
         with
         [
             worker=core::worker_thread
         ]

I wonder why it need to generate function overriding operator '='.

Is there any simple solution?