README.md

Module kotlinx-coroutines-core

Core primitives to work with coroutines.

Coroutine builder functions:

Name	Result	Scope	Description
launch	Job	CoroutineScope	Launches coroutine that does not have any result
async	Deferred	CoroutineScope	Returns a single value with the future result
produce	ReceiveChannel	ProducerScope	Produces a stream of elements
runBlocking	T	CoroutineScope	Blocks the thread while the coroutine runs

Coroutine dispatchers implementing CoroutineDispatcher:

Name	Description
Dispatchers.Default	Confines coroutine execution to a shared pool of background threads
Dispatchers.Unconfined	Does not confine coroutine execution in any way

More context elements:

Name	Description
NonCancellable	A non-cancelable job that is always active
CoroutineExceptionHandler	Handler for uncaught exception

Synchronization primitives for coroutines:

Name	Suspending functions	Description
Mutex	lock	Mutual exclusion
Channel	send, receive	Communication channel (aka queue or exchanger)

Top-level suspending functions:

Name	Description
delay	Non-blocking sleep
yield	Yields thread in single-threaded dispatchers
withContext	Switches to a different context
withTimeout	Set execution time-limit with exception on timeout
withTimeoutOrNull	Set execution time-limit will null result on timeout
awaitAll	Awaits for successful completion of all given jobs or exceptional completion of any
joinAll	Joins on all given jobs

Cancellation support for user-defined suspending functions is available with suspendCancellableCoroutine helper function. NonCancellable job object is provided to suppress cancellation with withContext(NonCancellable) {...} block of code.

Select expression waits for the result of multiple suspending functions simultaneously:

Receiver	Suspending function	Select clause	Non-suspending version
Job	join	onJoin	isCompleted
Deferred	await	onAwait	isCompleted
SendChannel	send	onSend	offer
ReceiveChannel	receive	onReceive	poll
ReceiveChannel	receiveOrNull	onReceiveOrNull	poll
Mutex	lock	onLock	tryLock
none	delay	onTimeout	none

Package kotlinx.coroutines

General-purpose coroutine builders, contexts, and helper functions.

Package kotlinx.coroutines.sync

Synchronization primitives (mutex).

Package kotlinx.coroutines.channels

Channels — non-blocking primitives for communicating a stream of elements between coroutines.

Package kotlinx.coroutines.flow

Flow — asynchronous cold stream of elements.

Package kotlinx.coroutines.selects

Select expression to perform multiple suspending operations simultaneously until one of them succeeds.

Package kotlinx.coroutines.intrinsics

Low-level primitives for finer-grained control of coroutines.

Package kotlinx.coroutines.test

Obsolete and deprecated module to test coroutines. Replaced with kotlinx-coroutines-test module.