Re: [boost] [string] proposal

Subject: Re: [boost] [string] proposal
From: Peter Dimov (pdimov_at_[hidden])
Date: 2011-01-21 11:19:22

Dean Michael Berris wrote:

> 1. The overhead of maintaining that table of reference counts may be 
> significant if you have a lot of strings created in your application.

No table is needed; the reference count is just placed before the string 
data in the allocated memory.

> 3. The reference count almost always will be implemented with atomic 
> counters to be efficient. In cases where the hardware doesn't support 
> these (in embedded environments)
...

Copying the string requires a memory allocation, which also grabs a lock. 
You're not likely to have a lock-free allocator if you don't have atomic 
operations.

> 2. In the case that you do have strings copied around, consider the case 
> in multi-threaded applications where you have different threads running on 
> different cores.

Copying the string data outweighs the reference count update because of the 
allocation.