Module inventory 

Shared discovery policy: collection failures are terminal; entry metadata is best effort.

Enums

ProcessFailure

Native process disappearance, distinguished from unreadable optional metadata.

Functions

collect

Collect an inventory; a collection/count failure never becomes an empty success. Entries without a usable identity return Ok(None); optional metadata and format failures are absorbed explicitly by the adapter. Err always rejects the whole call.

device_format

Discovery format and its availability. Zero/zero is the explicit unavailable sentinel.

device_identity

Keep name-based IDs when readable; otherwise use a selectable native ID and unknown name. Entries with neither identity are omitted. The native query is lazy for named devices.

device_identity_matches

Match either a name-based inventory ID or a native fallback, even after the name recovers.

macos_error_failure

Classify a Core Audio property failure while retaining structured native status.

macos_process_failure

macOS: kAudioHardwareBadObjectError (‘!obj’, 0x216f626a), ESRCH (3), and ENOENT (2) mean vanished. Other property/path errors mean unknown metadata.

optional

Optional property failures become explicit unknown values.

process_metadata

Interpret an optional process query: outer None means vanished; inner None means unknown. Used by adapters before the inventory collector, so unknown metadata keeps its PID.

require_device_format

Checked opening retains the original typed cause and explains how to retry.

selected_output_device

Validate the selected or default output device before device-scoped capture starts.

windows_error_failure

Classify a Windows process failure from its retained native HRESULT.

windows_process_failure

Windows: ERROR_INVALID_PARAMETER (87, HRESULT 0x80070057) means vanished. ERROR_ACCESS_DENIED (5, 0x80070005), and all other metadata errors, mean unknown.