Re: MAP and Vector clear is not releasing memory

From: Marshall Clow (mclow.lists_at_[hidden])
Date: 2025-02-26 14:34:49

On Feb 25, 2025, at 10:33 PM, Murali Kishore via Boost <boost_at_[hidden]> wrote:
> 
> Hi,
> 
> map and vector stored in shared memory using boost apis and called clear to
> release memory. when i insert same key i see old data present. want to
> check using boost map.clear or vec.clear is not removing content.
> 
> Example:
> 
> pod_list[] (vector contains following 3 members)
> pod_info  {
> 
>                pod_id
>                du_map.
>               cell_map.
> 
>             }
> 
> Step 1: Added elements
> 
> Step 2: pod_list.clear();
> 
> Step 3:  observed no elements in pod_list empty
> 
> Step 4:  Added only key
> 
> pod_info.pod_id = 1;
> 
> pod_list.insert(pod_info);
> 
> Step 5: i see old content map to this pod_id. after this expecting
> du_map.size and cell_map size is empty. but du_map,cell_map content is same
> as before clear
> 
> want to check is clear will not remove memory? is any other best way to
> clean this vector.

vector::clear() does not free memory allocated by the vector to store objects; it calls destructors for the objects it holds.

See this stack overflow post (from 2012)
        https://stackoverflow.com/questions/10464992/c-delete-vector-objects-free-memory

— Marshall