ACID means more than atomic updates, though. To be ACID-compliant, you'd have to be able to group several changes to the registry and have them take effect either all at once or not at all.

> To be ACID-compliant, you'd have to be able to group several changes to the registry and have them take effect either all at once or not at all.

You mean transactions? Windows registry supports them since Vista when they added Kernel Transaction Manager: https://msdn.microsoft.com/en-us/library/windows/desktop/bb9...

See CreateTransaction, RegCreateKeyTransacted, RegOpenKeyTransacted, CommitTransaction[Async], RollbackTransaction[Async] APIs.

I stand corrected. Good to know, thank you!

To be fair, I’ve never used KTM in my apps.

In cases when I need to write several values atomically (e.g. in a program with persistent window positions, after user moved a window I want to write all 4 coordinates of the rectangle), I just keep them in a single value, either string or binary. Even without KTM, registry API already guarantees value writes are atomic.

A word for that is transactional.

It's implied by the I (isolation).