How to keep element address in container

[Kai Wu]

Hello,

It turns out that STL vector does not assure the constness of its stored
element address (memory location),
i guess by the time it dynamicly allocates new memory as new element get
pushed in, it might copy stored elements
to new locations.

Is there any container implementation attempted doing so or how to instruct
STL to keep the address of those stored elements ?
array might do, but it lacks some flexibility ... it helps a lot if clint
code could reference the elements in the container
by each individual address.

Regards

[Jonathan Turkanis]

Kai Wu wrote:

Hello,

It turns out that STL vector does not assure the constness of its
stored element address (memory location),
i guess by the time it dynamicly allocates new memory as new element
get pushed in, it might copy stored elements
to new locations.

Is there any container implementation attempted doing so or how to
instruct STL to keep the address of those stored elements ?
array might do, but it lacks some flexibility ... it helps a lot if
clint code could reference the elements in the container
by each individual address.

It's not clear what you mean by assuring the constness of the stored element
address.

Jonathan

[rajkumar]

Kai Wu wrote:

Hello,

It turns out that STL vector does not assure the constness of its stored element address (memory location),
i guess by the time it dynamicly allocates new memory as new element get pushed in, it might copy stored elements
to new locations.

Is there any container implementation attempted doing so or how to instruct STL to keep the address of those stored elements ?
array might do, but it lacks some flexibility ... it helps a lot if clint code could reference the elements in the container
by each individual address.

Regards

If you have a vector of pointers the address wont change

If you have a vector of objects then the address of objects will change
anytime the vector grows. You can reserve the size of vector before
adding any elements and this wont happen but I would recommend making a
vector of smart_ptrs instead

Raj

[Llewelly]

"Kai Wu" <ka******@nokia.com> writes:

[snip]

Is there any container implementation attempted doing so or how to instruct
STL to keep the address of those stored elements ?

[snip]

Here is a list of stadnard containers which do not invalidate
references to or addresses of elements:

list, map, set, multiset, multimap .

In addition to these there is deque, which does not invalidate
addresses or references when inserts to either end are performed,
but does invalidate references and addresses when inserts to the
middle are performed.

None of these containers is quite like vector, but one of them is
likely to fit your needs. Read about each of them and decide.