Re: [RFA 02/22] Use RAII to save and restore scalars

Tom Tromey
2016-10-01T04:23:37Z

Pedro> Guess we could have the copy constructor actually move instead of
Pedro> copy, setting the copied-from's pointer member to NULL, and then
Pedro> have the destructor do nothing if the pointer is NULL.

Tom> Yeah. I took this approach. I'm not super thrilled with it, but at the
Tom> same time it's not *too* bad.

Scratch that, I spoke too soon. I couldn't get this to work.

I don't understand why the 2-argument form of make_scoped_restore
requires a copy constructor while the 1-argument form does not.

However, once you need a copy constructor, it doesn't seem possible
without a move constructor. The issue is that a copy constructor take a
const reference, so you can't modify the fields of the original.

Removing the 2-argument form seems to work. Though like I said, I don't
know why.

Also, as an aside, I found I was using nullptr in my patches, but this
isn't C++03. I think -std=c++03 is going to be needed or else it will
be too easy to slip in C++11-isms. Now, I do think C++11 is really much
better, but my understanding is that C++03 is what gdb decided on.

Tom