//arrow-fx-stm/arrow.fx.stm/STM/isEmpty
common open fun <A> TMVar<A>.isEmpty(): Boolean
Check if a TMVar is empty. This function never retries.
import arrow.fx.stm.TMVar
import arrow.fx.stm.atomically
suspend fun main() {
//sampleStart
val tmvar = TMVar.empty<Int>()
val result = atomically {
tmvar.isEmpty()
}
//sampleEnd
println("Result $result")
}
Because the state of a transaction is constant there can never be a race condition between checking if a `TMVar` is empty and subsequent reads in the *same* transaction.
common open fun <A> TQueue<A>.isEmpty(): Boolean
Check if a TQueue is empty.
import arrow.fx.stm.TQueue
import arrow.fx.stm.atomically
suspend fun main() {
//sampleStart
val tq = TQueue.new<Int>()
val result = atomically {
tq.isEmpty()
}
//sampleEnd
println("Result $result")
}
This function never retries.
This function has to access both [TVar](../-t-var/index.html)'s and thus may lead to increased contention, use sparingly.
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