That's interesting. So the container remembers what sort of a reserve request I made on it, and uses that as the preferred size whenever the element count of the container changes?
Yes. Calling reserve typically means that you do not want to have extra reallocations while updating the container's content (instead you allocate sufficient space upfront). In case of QList, we make sure there are no reallocations happening unless absolutely necessary, e.g. appending 1 element when size == capacity would allocate bigger memory chunk - reservation is a hint, but not an obligation. Consequently, QList's shrinking erase also does not shrink when capacity is reserved. -- Best Regards, Andrei ________________________________ From: Ville Voutilainen <[email protected]> Sent: Thursday, September 10, 2020 10:39 AM To: Andrei Golubev <[email protected]> Cc: [email protected] <[email protected]> Subject: Re: [Development] Important recent changes in QList/QString/QByteArray On Wed, 9 Sep 2020 at 16:38, Andrei Golubev <[email protected]> wrote: > > I don't understand what this means. Am I supposed to reserve a > container to its current size before erasing elements > from it, if I don't want the erase to shrink it? > > Yes. That's interesting. So the container remembers what sort of a reserve request I made on it, and uses that as the preferred size whenever the element count of the container changes?
_______________________________________________ Development mailing list [email protected] https://lists.qt-project.org/listinfo/development
