Module Rig.Local

The type for keys of values of type 'a kept per device.

new_key init is a key whose value on a device d is init d. A key is never freed, so a library must make its keys once, such as at a module's top level.

get k d is k's value on d. The first get of k on d runs init d and stores its result, which every later get answers. A get that finds its value takes no lock and allocates nothing.

• init d runs on the calling domain holding no lock of rig's, so it may call any of rig's functions, get of any key included.
• Gets that race on a device with no value may each run init d. The first value stored is kept and every get answers it, so init makes values of which a spare is harmless.
• An init that gets k on d runs a nested init, whose value is stored first, so both gets answer it.
• If init d raises, get raises it and stores nothing.

Raises Lost if d is lost.