Dear list,

I’m using boost::fast_pool_allocator to replace the default allocator in a map.  This works great, but I’m having a bit of trouble freeing the memory explicitly. 

I’d like to call boost::singleton_pool::purge_memory(), but I don’t know how to instantiate the correct version.  Is there a way to determine the size of the chunks the map allocator will require?  I have determined by debugging that the size is 28 bytes, but I imagine that this is dependent on the particular implementation of map. 

Below is a sample program which illustrates the situation.  Any guidance would be very appreciated.

- Finley

///////////////////////////////////////////////////////////////////////////

#include <assert.h>

#include <iso646.h>

#include <map>

#include <boost\pool\pool_alloc.hpp>

class mydata

{

public:

mydata() {}

mydata( int _a, short _b,  char _c ) :

a(_a), b(_b), c(_c) {}

int a ;

short b ;

char c ;

};

typedef std::map< int, mydata,

std::less<int>,

boost::fast_pool_allocator< std::pair<int, mydata> > > mymap ;

int _tmain(int argc, _TCHAR* argv[])

{

   {

mymap m ;

for ( int i = 0 ; i < 10000 ; i++ )

m[i] = mydata( i, i, i ) ;

   }

bool memory_freed = boost::singleton_pool< boost::fast_pool_allocator_tag, sizeof( std::pair<int,mydata> ) >::purge_memory() ;

//bool memory_freed = boost::singleton_pool< boost::fast_pool_allocator_tag, 28 >::purge_memory() ;

assert( memory_freed ) ;

return 0;

}