[boost] pool allocator question

From: Steve Kettle (skettle2000_at_[hidden])
Date: 2007-08-14 18:14:26

I have a question about the memory pool allocation that boost implements.  Suppose we do the following: 
   std::vector<int, boost::pool_allocator<int> > v; 
   for (int i = 0; i < 10; ++i) 
     v.push_back(-1); 
 
And the std::vector<int> is implemented so that it starts out with 
 reserved space of 1 and doubles space every time.  So At the end of the above loop v will have size 10 and reserved size 16. 
 
Does the boost allocator mean that there will memory arrays lieing 
 around of size 1,2,4,8 that can be reused ? 
 
Eg if you do this: 
 
  std::vector<int, boost::pool_allocator<int> > v; 
   for (int i = 0; i < 10; ++i) 
     v.push_back(-1); 
 
  std::vector<int, boost::pool_allocator<int> > v2; 
   for (int i = 0; i < 8; ++i) 
     v2.push_back(-1); 
 
There will be no system call needed to get more memory - 
 v2 will just reuse the memory in the pool_allocator<int> ? 
    
   Thanks.
Steve.

       
---------------------------------
Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more.