runBlocking

Runs a new coroutine and blocks the current thread until its completion.

It is designed to bridge regular blocking code to libraries that are written in suspending style, to be used in main functions and in tests.

Calling runBlocking from a suspend function is redundant. For example, the following code is incorrect:

suspend fun loadConfiguration() {
    // DO NOT DO THIS:
    val data = runBlocking { // <- redundant and blocks the thread, do not do that
        fetchConfigurationData() // suspending function
    }

Here, instead of releasing the thread on which loadConfiguration runs if fetchConfigurationData suspends, it will block, potentially leading to thread starvation issues.

Runs a new coroutine and blocks the current thread interruptibly until its completion.

It is designed to bridge regular blocking code to libraries that are written in suspending style, to be used in main functions and in tests.

Calling runBlocking from a suspend function is redundant. For example, the following code is incorrect:

suspend fun loadConfiguration() {
    // DO NOT DO THIS:
    val data = runBlocking { // <- redundant and blocks the thread, do not do that
        fetchConfigurationData() // suspending function
    }

Here, instead of releasing the thread on which loadConfiguration runs if fetchConfigurationData suspends, it will block, potentially leading to thread starvation issues.

The default CoroutineDispatcher for this builder is an internal implementation of event loop that processes continuations in this blocked thread until the completion of this coroutine. See CoroutineDispatcher for the other implementations that are provided by kotlinx.coroutines.

When CoroutineDispatcher is explicitly specified in the context, then the new coroutine runs in the context of the specified dispatcher while the current thread is blocked. If the specified dispatcher is an event loop of another runBlocking, then this invocation uses the outer event loop.

If this blocked thread is interrupted (see Thread.interrupt), then the coroutine job is cancelled and this runBlocking invocation throws InterruptedException.

See newCoroutineContext for a description of debugging facilities that are available for a newly created coroutine.

Parameters

Runs new coroutine and blocks current thread interruptibly until its completion.

It is designed to bridge regular blocking code to libraries that are written in suspending style, to be used in main functions and in tests.

Calling runBlocking from a suspend function is redundant. For example, the following code is incorrect:

suspend fun loadConfiguration() {
    // DO NOT DO THIS:
    val data = runBlocking { // <- redundant and blocks the thread, do not do that
        fetchConfigurationData() // suspending function
    }

Here, instead of releasing the thread on which loadConfiguration runs if fetchConfigurationData suspends, it will block, potentially leading to thread starvation issues.

The default CoroutineDispatcher for this builder in an implementation of EventLoop that processes continuations in this blocked thread until the completion of this coroutine. See CoroutineDispatcher for the other implementations that are provided by kotlinx.coroutines.

When CoroutineDispatcher is explicitly specified in the context, then the new coroutine runs in the context of the specified dispatcher while the current thread is blocked. If the specified dispatcher implements EventLoop interface and this runBlocking invocation is performed from inside of the this event loop's thread, then this event loop is processed using its processNextEvent method until coroutine completes.

If this blocked thread is interrupted (see Thread.interrupt), then the coroutine job is cancelled and this runBlocking invocation throws InterruptedException.

See newCoroutineContext for a description of debugging facilities that are available for newly created coroutine.

Parameters