Re: [Boost-users] [1.33][ptr_container] bug in erase() in associativecontainers?

"Malte Clasen" wrote in message news:deg2p6$ce0$1@sea.gmane.org...

Hi,

the erase() method (defined in associative_ptr_container.hpp, line 104) seems a bit strange:

size_type erase( const key_type& x ) // nothrow { BOOST_ASSERT( !this->empty() ); iterator i = find( x ); // nothrow if( i == this->end() ) // nothrow return 0; // nothrow this->remove( i ); // nothrow return this->c_private().erase( i.base() ); // nothrow }

http://cvs.sourceforge.net/viewcvs.py/boost/boost/boost/ptr_container/detail/associative_ptr_container.hpp?rev=1.4&view=markup

My compiler (vc++7.1) complained about the unknown find() when I called erase() on ptr_map. "find" is not declared neither in this class nor in its base class. The closest valid call I could think of would be

this->c_private().find( x )

hm...maybe I overlooked something...I will look at that later.

. But there seems to be a nicer solution:

size_type erase( const key_type& x ) // nothrow { BOOST_ASSERT( !this->empty() ); return this->c_private().erase( x ); // nothrow }

This compiles fine and does just what I want it to do, even nothrow is guaranteed (I checked the vc++ reference for std::map). Now I wonder why erase() is implemented differently in Boost 1.33. Is there anything I overlooked?

deleting the object itself...not just the pointer.

Btw, is there a rationale for the declaration of insert()?

std::pair insert( key_type& k, value_type x );

http://cvs.sourceforge.net/viewcvs.py/boost/boost/boost/ptr_container/ptr_map_adapter.hpp?rev=1.12&view=auto

Passing key_type by non-const reference caused some unaesthetic constructs in my code because return values (temporaries) cannot be used directly.

indeed. but this is the only way to gain exception-safety. -Thorsten