How to detect free/unfree memory segments?

[Suliman via Digitalmars-d-learn]

On Saturday, 24 December 2016 at 01:15:43 UTC, jkpl wrote:
> On Friday, 23 December 2016 at 06:18:02 UTC, Suliman wrote:
>> I would like to visualize how GC works and display free/not 
>> free memory segments.
>> How I can understand which of them are used and which not?
>>
>> Could anybody explain what dangerous of memory fragmentation 
>> in languages without GC? Am I right understand that there is 
>> stay some small memory chunks that very hard to reuse?
>
> You start with a wrong assumption. The C malloc functions is 
> not just a nasty and mean memory provider. Several 
> implementations uses internally freelists. Which means that the 
> gaps created by a free() may be filled again.
>
> For example
> - TCMallocator use free lists
> - GCC C malloc use free lists (as stated here 
> http://www.gnu.org/software/libc/manual/html_node/Freeing-after-Malloc.html)
> - for snn.lib malloc (used by DMD win32) I can't say.

So there is no any problems with memory fragmentation and all 
used memory arr successfuly reuse?