help on std::vector

[Tim]

Dear All,

std::vector seems using the copy constructor to allocate memory when
needed. Is it possible to control the memory allocation, such as by
using my own allocator? My question is as follow:

I have a smart pointer my_ptr, and the copy constructor uses deep
copy, however I want it to be shallow copy in std::vector when
reallocate memory. How can I implement it?

This seems a very challenging question as least for me. I appreciate
your kind help.

Best regards,

Tim

 

[AnonMail2005]

Dear All,

std::vector seems using the copy constructor to allocate memory when
needed. Is it possible to control the memory allocation, such as by
using my own allocator? My question is as follow:

I have a smart pointer my_ptr, and the copy constructor uses deep
copy, however I want it to be shallow copy in std::vector when
reallocate memory. How can I implement it?

This seems a very challenging question as least for me. I appreciate
your kind help.

Best regards,

Tim

1. You can use reserve on the vector, if you know the maximum number
of elements
that you'll use, to prevent re-allocation and copying.

2. Use a vector of raw pointers if the vector is being used as
temporary storage
(e.g. inside a function) to work with the elements.

3. Use a vector of some other pointer class that does shallow copy.

Hope that helps.

 

[Gianni Mariani]

Dear All,

std::vector seems using the copy constructor to allocate memory when
needed. Is it possible to control the memory allocation, such as by
using my own allocator? My question is as follow:

I have a smart pointer my_ptr, and the copy constructor uses deep
copy, however I want it to be shallow copy in std::vector when
reallocate memory. How can I implement it?

This seems a very challenging question as least for me. I appreciate
your kind help.

There are some simple things you can do but it's not trivial to get
right. I think you're going to need to implement your own container to
do this right.