The event, lock, and log PODs embed fixed-cap arrays sized to the protocol's own limits, with a count field saying how many slots are live. char arrays are NUL-terminated.

Each value is a wire byte; the canonical meaning lives on Enums. The *Kind enums (and MediusClass) tag which arm of a built value (MediusUsage, MediusMotion, MediusCatchEvent) is populated.

enum MediusDeviceKind : uint8_t

The kind field of a MediusDeviceInfo, from the cloned device's Boot-interface protocol. Also what medius_device_find_mouse_box / _find_keyboard_box select on. See DeviceKind.

enum MediusButton : uint8_t   /* values match the firmware button id */

The button an inject call drives. Ids on Usage IDs.

enum MediusAction : uint8_t

The override action shared by inject calls, whether a button, key, or media usage. See the injection model.

enum MediusClass : uint8_t

The kind tag of a MediusUsage you build with medius_usage_button/_key/_media.

enum MediusMotionKind : uint8_t

Tags the MediusMotion you build with medius_motion_cursor/_wheel. See Move.

enum MediusLockTargetKind : uint8_t

The kind of a MediusLockTarget. See Lock.

enum MediusLockDirection : uint8_t

For an axis or wheel it's a sign; for a usage it's an edge. See LOCK.

enum MediusEdge : uint8_t

The edge of a MediusClipTrigger's on usage that runs its action. Same wire values as MediusLockDirection. See Clip.

enum MediusClipAction : uint8_t

What a bound MediusClipTrigger does to the clip on its edge; the same verbs as the medius_clip_start/_stop/... calls. See Clip.

enum MediusBlanket : uint8_t

A whole input group: which one medius_device_lock_all/_unlock_all block in one call, and the scope medius_clip_set_autolock auto-locks while a clip plays. See Lock.

The values are ABI-local ordinals (matching the crate's Blanket order), not the CLIP_LOCK_* wire bits.

enum MediusLedTarget : uint8_t

See LED.

enum MediusLedMode : uint8_t

See LED. Solid / Blink use the command's level.

enum MediusRebootTarget : uint8_t

See Admin.

enum MediusEmitMode : uint8_t

See Options.

enum MediusCatchEventKind : uint8_t

Tells you which member of the MediusCatchEvent union to read. See Catch.

enum MediusLogLevel : uint8_t

The severity of a MediusLogLine. See Logs & counters.

typedef uint8_t MediusCatchMask;   /* OR the MEDIUS_CATCH_MASK_* bits */

The subscription you hand to medius_device_catch_events. See Catch.

typedef uint8_t MediusKey;   /* modifiers are 0xE0 to 0xE7 */

A raw HID keyboard usage passed to the key calls. Pass any usage byte, or one of the MEDIUS_KEY_* macros. The full set of usages is on Usage IDs.

typedef uint16_t MediusMediaKey;

A raw Consumer usage passed to the media calls. Pass any 16-bit usage, or a MEDIUS_MEDIA_* macro. The full set is on Usage IDs.

enum MediusFrameType : uint8_t   /* always defined; read only by the mock recorder */

The TYPE byte of a wire frame, used with the mock recorder (medius_mock_saw / medius_mock_recorded_frame). See the mock feature.

Three small PODs you build with a helper and hand to a call. The medius_*_* constructors set the kind tag and the right field for you.

What medius_device_inject drives. Build with medius_usage_button(...), _key(...), or _media(...); id holds the button id or usage per kind. See Inject.

What medius_device_move_axis drives. Build with medius_motion_cursor(dx, dy) or medius_motion_wheel(delta). See Move.

Passed to medius_device_lock / _unlock. Build it with medius_lock_target_axis or medius_lock_target_usage; usage is read only when kind is USAGE. See Lock.

Each medius_device_query_* / _caps / _counters call fills one of these by value. Canonical field docs are on Structs; query semantics on Requests.

From medius_device_query_version. Set the box's name with medius_device_set_name.

From medius_device_query_health.

From medius_device_device_info; all-zero/empty when nothing is cloned. product is a NUL-terminated UTF-8 string.

From medius_device_caps: a mouse half and a keyboard half plus the per-class change-driven flags. Test it with medius_caps_has_mouse, medius_caps_has_keyboard, medius_caps_is_composite.

The mouse half of MediusCaps; all-zero when no mouse interface is bound.

The keyboard half of MediusCaps; all-zero when no keyboard is bound. n_keys == 0xFF signals an NKRO bitmap.

From medius_device_query_rate. Convert to Hz with medius_rate_native_hz(rate, &hz) (returns false when there's no continuous cadence).

From medius_device_query_stats. A nonzero tx_drops or tx_wedges means delivery degraded under load.

From medius_device_query_locks: entries[0..n], one per locked target. Test a target/direction with medius_locks_is_locked(&locks, target, dir), which reports a match from a specific entry or a covering whole-class is_blanket lock. Wire layout on the native LOCKS reply.

From medius_device_query_catch. A nonzero dropped means the box shed events under back-pressure.

From medius_device_query_imperfect. See Options.

From medius_device_query_emit_pace. See Options.

From medius_device_counters. See Logs & counters.

Filled by medius_find_ports; path and serial are NUL-terminated. Canonical docs on PortInfo.

Filled by medius_list: one entry per connected box, each opened and handshaked in turn. See BoxInfo.

The values you read off the catch and log streams. Catch semantics on Catch; canonical docs on Structs.

The user's real motion at the merge point, before any lock suppression or injection. Surfaces as the Motion arm of a MediusCatchEvent.

The held usages of one class (button, key, or media; modifiers are key usages 0xE0 to 0xE7) in usages[0..n], buttons and keys the same shape. Test one with medius_usage_event_is_held(&event, usage), or diff successive snapshots for edges.

struct MediusCatchEvent {
    MediusCatchEventKind kind;
    union MediusCatchEventData { MediusMotionEvent motion; MediusUsageEvent usages; } data;
}

Written by medius_event_stream_recv and friends. Read the union member named by kind.

Written by medius_log_stream_recv; text is NUL-terminated.

A managed binding you add with medius_clip_bind: when on hits edge, the box runs action on the clip. Build the on usage with the medius_usage_* helpers. Concept on Clip.

From medius_clip_query_config: the auto-lock scope, the loop/retain/finalize scalars, and the live trigger set. Concept on Clip.

From medius_clip_query_status; state is a MediusClipState. Concept on Clip.

enum MediusStatus : int32_t   /* MEDIUS_STATUS_OK == 0; everything else is a failure */

Every fallible call returns a MediusStatus and writes its result through an out-param. On failure the detail lives in thread-local state. Read it before the next call on that thread overwrites it. Canonical mapping on Errors.

MediusDevice *dev = NULL;
if (medius_device_find(&dev) != MEDIUS_STATUS_OK) {
    char buf[256];
    medius_last_error_message(buf, sizeof buf);
    fprintf(stderr, "open failed: %s\n", buf);
    return 1;
}