Async.h File Reference

#include "Async/Future.h"
#include "Async/TaskGraphInterfaces.h"
#include "Containers/UnrealString.h"
#include "CoreTypes.h"
#include "HAL/PlatformAffinity.h"
#include "HAL/PlatformProcess.h"
#include "HAL/Runnable.h"
#include "HAL/RunnableThread.h"
#include "HAL/ThreadSafeCounter.h"
#include "Misc/AssertionMacros.h"
#include "Misc/CoreStats.h"
#include "Misc/Fork.h"
#include "Misc/IQueuedWork.h"
#include "Misc/QueuedThreadPool.h"
#include "Containers/Ticker.h"
#include "Stats/Stats.h"
#include "Templates/Function.h"
#include "Templates/UnrealTemplate.h"

Go to the source code of this file.

Classes
class	FAsyncGraphTaskBase
class	TAsyncGraphTask< ResultType >
class	TAsyncRunnable< ResultType >
class	TAsyncQueuedWork< ResultType >
struct	FAsyncThreadIndex

Enumerations
enum class	EAsyncExecution {   TaskGraph , TaskGraphMainThread , TaskGraphMainTick , Thread ,   ThreadIfForkSafe , ThreadPool }

Functions
template<typename ResultType , typename CallableType >
void	SetPromise (TPromise< ResultType > &Promise, CallableType &&Callable)
template<typename CallableType >
void	SetPromise (TPromise< void > &Promise, CallableType &&Callable)
template<typename CallableType >
auto	Async (EAsyncExecution Execution, CallableType &&Callable, TUniqueFunction< void()> CompletionCallback=nullptr) -> TFuture< decltype(Forward< CallableType >(Callable)())>
template<typename CallableType >
auto	AsyncPool (FQueuedThreadPool &ThreadPool, CallableType &&Callable, TUniqueFunction< void()> CompletionCallback=nullptr, EQueuedWorkPriority InQueuedWorkPriority=EQueuedWorkPriority::Normal) -> TFuture< decltype(Forward< CallableType >(Callable)())>
template<typename CallableType >
auto	AsyncThread (CallableType &&Callable, uint32 StackSize=0, EThreadPriority ThreadPri=TPri_Normal, TUniqueFunction< void()> CompletionCallback=nullptr) -> TFuture< decltype(Forward< CallableType >(Callable)())>
CORE_API void	AsyncTask (ENamedThreads::Type Thread, TUniqueFunction< void()> Function)

Enumeration Type Documentation

EAsyncExecution

enum class EAsyncExecution

strong

Enumerates available asynchronous execution methods.

Enumerator
TaskGraph	Execute in Task Graph (for short running tasks).
TaskGraphMainThread	Execute in Task Graph on the main thread (for short running tasks that are safe to run anywhere including inside other waits). Note: this could end up running inside the GC or inside PostLoads, code with delegates that can't be known to be safe in advance should opt for TaskGraphMainTick instead.
TaskGraphMainTick	Execute inside a Tick on the main thread (for short running tasks that needs to run at a safe place).
Thread	Execute in separate thread if supported (for long running tasks).
ThreadIfForkSafe	Execute in separate thread if supported or supported post fork (see FForkProcessHelper::CreateThreadIfForkSafe) (for long running tasks).
ThreadPool	Execute in global queued thread pool.

Function Documentation

Async()

template<typename CallableType >

auto Async	(	EAsyncExecution	Execution,
		CallableType &&	Callable,
		TUniqueFunction< void()>	CompletionCallback = nullptr
	)		-> TFuture<decltype(Forward<CallableType>(Callable)())>

Execute a given function asynchronously.

Usage examples:

// using global function int TestFunc() { return 123; }

TUniqueFunction<int()> Task = TestFunc(); auto Result = Async(EAsyncExecution::Thread, Task);

// using lambda TUniqueFunction<int()> Task = []() { return 123; }

auto Result = Async(EAsyncExecution::Thread, Task);

// using inline lambda auto Result = Async(EAsyncExecution::Thread, []() { return 123; }

Parameters

CallableType	The type of callable object.
Execution	The execution method to use, i.e. on Task Graph or in a separate thread.
Function	The function to execute.
CompletionCallback	An optional callback function that is executed when the function completed execution.

Returns

A TFuture object that will receive the return value from the function.

AsyncPool()

template<typename CallableType >

auto AsyncPool	(	FQueuedThreadPool &	ThreadPool,
		CallableType &&	Callable,
		TUniqueFunction< void()>	CompletionCallback = nullptr,
		EQueuedWorkPriority	InQueuedWorkPriority = EQueuedWorkPriority::Normal
	)		-> TFuture<decltype(Forward<CallableType>(Callable)())>

Execute a given function asynchronously on the specified thread pool.

Parameters

CallableType	The type of callable object.
ThreadPool	The thread pool to execute on.
Function	The function to execute.
CompletionCallback	An optional callback function that is executed when the function completed execution.

Returns

A TFuture object that will receive the return value from the function.

AsyncTask()

CORE_API void AsyncTask	(	ENamedThreads::Type	Thread,
		TUniqueFunction< void()>	Function
	)

Convenience function for executing code asynchronously on the Task Graph.

Parameters

Thread	The name of the thread to run on.
Function	The function to execute.

AsyncThread()

template<typename CallableType >

auto AsyncThread	(	CallableType &&	Callable,
		uint32	StackSize = 0,
		EThreadPriority	ThreadPri = TPri_Normal,
		TUniqueFunction< void()>	CompletionCallback = nullptr
	)		-> TFuture<decltype(Forward<CallableType>(Callable)())>

Execute a given function asynchronously using a separate thread.

Parameters

CallableType	The type of callable object.
Function	The function to execute.
StackSize	stack space to allocate for the new thread
ThreadPri	thread priority
CompletionCallback	An optional callback function that is executed when the function completed execution.

Returns

A TFuture object that will receive the return value from the function.

SetPromise() [1/2]

template<typename ResultType , typename CallableType >

void SetPromise ( TPromise< ResultType > &  Promise, CallableType &&  Callable  )

inline

Template for setting a promise value from a callable.

SetPromise() [2/2]

template<typename CallableType >

void SetPromise ( TPromise< void > &  Promise, CallableType &&  Callable  )

inline