Hacker News new | ask | show | jobs
by catnaroek 3744 days ago
Same in C++. There's `std::vector::reserve`, which grows the vector's underlying physical buffer, without logically adding any new elements. If you `reserve` enough capacity before inserting anything, it's even a `O(1)` operation.
1 comments

Vector and possibly string have that. The vast majority of STL structures do not.
All containers from the C++ standard library (please don't call it STL, that's Stepanov's original library) can be parameterized by an allocator. You can use whatever allocation policy you like best. However, most people use the default allocator because it's good enough.

In any case, while C++ has lots of defects, “loss of control relative to what C gives you” isn't one of them.

(a bit of topic - but I'm humbly trying to learn more...) I've got zero experience writing allocators. Is there some common ones you use provided somewhere? Do you write your own? (in which case can you point me to where to learn to do that properly)
I don't write allocators myself, but Boost has a pool allocator library [http://www.boost.org/doc/libs/1_60_0/libs/pool/doc/html/inde...], which conforms to the Allocator concept defined in the standard library [http://en.cppreference.com/w/cpp/concept/Allocator].
Thank you
Yeah, that's true.