Errors

Every verb answers Error!T, one error per final status of the C interface. The engine checks every shape it can see; the binding checks only what never crosses the boundary, like a key run longer than its rows, and reports the status the engine would have. The engine’s static detail message rides an Outcome you lend: diagnosed(&outcome) on the index or a blocking receiver copies every call’s final outcome into it, a constructor’s config takes one as diagnostics, and a Deferred answers its own through message. The binding’s own refusals land there too, with a message of their own. One set covers every verb rather than a narrower one per verb, since nothing in the ABI bounds which status a given call may report.

var outcome: usearch.Outcome = .{};
_ = index.on(executor).diagnosed(&outcome).search(queries, 10, &arena, .{}) catch |failure| {
    std.log.err("{s}: {s}", .{ @errorName(failure), outcome.text() });
    return failure;
};
var copy = try usearch.DenseIndex.loadRam("index.safegraphs", .{ .diagnostics = &outcome });

Status, Scalar, Mood, Residency and DenseMetric carry the C enumerators’ values, and their name and fromName spell them through the C name tables, fromName answering null for text no table spells.

std.debug.print("{s}\n", .{usearch.Status.contended.name()}); // contended
const metric = usearch.DenseMetric.fromName("inner") orelse return error.UnknownMetric;