delete[]

[AS]

Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int) memory

delete []pBuf // this will delete all the memory allocated to pBuf

Question: How come the application knows that it has to delete memory of
pBuf for 10 * sizeof(int) from the statement "delete []pBuf "?


Pls. reply back


John

 

[Kira Yamato]

Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int) memory

delete []pBuf // this will delete all the memory allocated to pBuf

Question: How come the application knows that it has to delete memory of
pBuf for 10 * sizeof(int) from the statement "delete []pBuf "?


Pls. reply back


John

Same way how free() knows how much memory to reclaim from malloc(): It
keeps internal data structure on what pieces of memory were issued.

 

[AS]

Thanx for the reply. I guessed the same. Can you explain in detail or any
sample code to demonstrate this ?

Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int) memory

delete []pBuf // this will delete all the memory allocated to pBuf

Question: How come the application knows that it has to delete memory of
pBuf for 10 * sizeof(int) from the statement "delete []pBuf "?


Pls. reply back


John

Same way how free() knows how much memory to reclaim from malloc(): It
keeps internal data structure on what pieces of memory were issued.

 

[Jim Langston]

Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int)
memory delete []pBuf // this will delete all the memory allocated to
pBuf Question: How come the application knows that it has to delete
memory of pBuf for 10 * sizeof(int) from the statement "delete
[]pBuf "?

Same way how free() knows how much memory to reclaim from malloc(): It
keeps internal data structure on what pieces of memory were
issued.

Thanx for the reply. I guessed the same. Can you explain in detail or
any sample code to demonstrate this ?

It's the compiler/OS that keeps track. It may be done differently in
different compilers and OSes. I think you gave the perfect example, what
more would you need?

 

[AS]

I would like to know how this is happening internally, suppose that if we
have to write our own Memory Manager which handle these ?

On 2007-12-24 00:57:39 -0500, "AS" <[email protected]>
said:
Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int)
memory delete []pBuf // this will delete all the memory allocated
to
pBuf Question: How come the application knows that it has to delete
memory of pBuf for 10 * sizeof(int) from the statement "delete
[]pBuf "?
Same way how free() knows how much memory to reclaim from malloc(): It
keeps internal data structure on what pieces of memory were
issued.

Thanx for the reply. I guessed the same. Can you explain in detail or
any sample code to demonstrate this ?

It's the compiler/OS that keeps track. It may be done differently in
different compilers and OSes. I think you gave the perfect example, what
more would you need?

 

[Ian Collins]

AS wrote:
Please don't top-post.

On 2007-12-24 00:57:39 -0500, "AS" <[email protected]>
said:
Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int)
memory delete []pBuf // this will delete all the memory allocated
to
pBuf Question: How come the application knows that it has to delete
memory of pBuf for 10 * sizeof(int) from the statement "delete
[]pBuf "?
Same way how free() knows how much memory to reclaim from malloc(): It
keeps internal data structure on what pieces of memory were
issued.
Thanx for the reply. I guessed the same. Can you explain in detail or
any sample code to demonstrate this ?

It's the compiler/OS that keeps track. It may be done differently in
different compilers and OSes. I think you gave the perfect example, what
more would you need?
Or quote signatures.

I would like to know how this is happening internally, suppose that if we
have to write our own Memory Manager which handle these ?

The answer is part of your operating system or runtime libraries. If
you can , consult the source for those. Writing your own memory manager
is an excellent way to understand the problems involved with dynamic
memory management.

 

[Kira Yamato]

Hello,
consider the following statements,
int *pBuf = new int[10]; //this will allocate 10*sizeof(int) memory

delete []pBuf // this will delete all the memory allocated to pBuf

Question: How come the application knows that it has to delete memory of
pBuf for 10 * sizeof(int) from the statement "delete []pBuf "?


Pls. reply back


John

Same way how free() knows how much memory to reclaim from malloc(): It
keeps internal data structure on what pieces of memory were issued.

Thanx for the reply. I guessed the same. Can you explain in detail or any
sample code to demonstrate this ?

Better. I'll give you a hint, and you implement the code. Then we'll
discuss it.

Hint: Pretend you already have all of the memory a 64-bits pointer can
address. Now, pretend you're the "librarian" not of books but instead
of these memory bytes. You job is to do book-keeping of what memory
has been loaned out and returned back.

Design a data-structure that does this book-keeping.

Write the "loan-out" function and the "return-back" function.

Try it. It'll be more rewarding to you this way.

 

[Abhishek Padmanabh]

I would like to know how this is happening internally, suppose that if we
have to write our own Memory Manager which handle these ?

Consider going through the C++ FAQ lite -
http://www.parashift.com/c++-faq-lite/freestore-mgmt.html#faq-16.14