How memory function free() knows how much memory to free.

[Panduranga Chary]

Hi,

How does the memory management function 'free()' frees the memory
pointed by a pointer variable at run time. how does it know the size.
if there is way when free() can do, then why can't we do it
externally?.
Thanks
Panduranga Chary

[MisterE]

Hi,

How does the memory management function 'free()' frees the memory
pointed by a pointer variable at run time. how does it know the size.
if there is way when free() can do, then why can't we do it
externally?.

When you malloc memory, the size of the allocated block is stored somewhere.
What do you mean by externally?

[Keith Thompson]

Panduranga Chary <pr******@gmail.comwrites:

How does the memory management function 'free()' frees the memory
pointed by a pointer variable at run time. how does it know the size.
if there is way when free() can do, then why can't we do it
externally?.

The comp.lang.c FAQ is at <http://www.c-faq.com/>.
You've just asked question 7.26.

--
Keith Thompson (The_Other_Keith) <ks***@mib.org>
[...]
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"