require

fun require(value: Boolean)(source)

Validates an argument precondition.

Returns normally when value is true. On failure, the exception message is Failed requirement.. Use the lazy-message overload to provide more context.

Parameters

value

condition that must be true.

See also

Throws


inline fun require(value: Boolean, lazyMessage: () -> Any)(source)

Validates an argument precondition, computing a message only on failure.

When value is true, lazyMessage is never called. Otherwise it runs once and its result is converted using toString(). Exceptions from the callback or conversion propagate unchanged. The inline callback supports non-local returns.

require(count >= 0) { "Negative count: $count" }

Parameters

value

condition that must be true.

lazyMessage

callback producing a non-null message value on failure.

Throws

if value is false and message construction completes normally.