Encapsulates a thread. More...

#include <juce_Thread.h>

Inheritance diagram for Thread:

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Collaboration diagram for Thread:

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Public Types
enum	{ realtimeAudioPriority = -1 }
	Special realtime audio thread priority. More...

typedef void *	ThreadID
	A value type used for thread IDs. More...

Public Member Functions
	Thread (const String &threadName, size_t threadStackSize=0)
	Creates a thread. More...

virtual	~Thread ()
	Destructor. More...

ThreadID	getThreadId () const noexcept
	Returns the ID of this thread. More...

const String &	getThreadName () const
	Returns the name of the thread. More...

bool	isThreadRunning () const
	Returns true if the thread is currently active. More...

void	notify () const
	Wakes up the thread. More...

virtual void	run ()=0
	Must be implemented to perform the thread's actual code. More...

void	setAffinityMask (uint32 affinityMask)
	Sets the affinity mask for the thread. More...

bool	setPriority (int priority)
	Changes the thread's priority. More...

void	signalThreadShouldExit ()
	Sets a flag to tell the thread it should stop. More...

void	startThread ()
	Starts the thread running. More...

void	startThread (int priority)
	Starts the thread with a given priority. More...

bool	stopThread (int timeOutMilliseconds)
	Attempts to stop the thread running. More...

bool	threadShouldExit () const
	Checks whether the thread has been told to stop running. More...

bool	wait (int timeOutMilliseconds) const
	Makes the thread wait for a notification. More...

bool	waitForThreadToExit (int timeOutMilliseconds) const
	Waits for the thread to stop. More...

Static Public Member Functions
static bool	currentThreadShouldExit ()
	Checks whether the current thread has been told to stop running. More...

static Thread *	getCurrentThread ()
	Finds the thread object that is currently running. More...

static ThreadID	getCurrentThreadId ()
	Returns an id that identifies the caller thread. More...

static void	setCurrentThreadAffinityMask (uint32 affinityMask)
	Changes the affinity mask for the caller thread. More...

static void	setCurrentThreadName (const String &newThreadName)
	Changes the name of the caller thread. More...

static bool	setCurrentThreadPriority (int priority)
	Changes the priority of the caller thread. More...

static void	sleep (int milliseconds)

static void	yield ()
	Yields the calling thread's current time-slot. More...

Private Member Functions
void	closeThreadHandle ()

void	killThread ()

void	launchThread ()

void	threadEntryPoint ()

Static Private Member Functions
static bool	setThreadPriority (void *, int)

Private Attributes
uint32	affinityMask = 0

WaitableEvent	defaultEvent

bool	isAndroidRealtimeThread = false

bool volatile	shouldExit = false

CriticalSection	startStopLock

WaitableEvent	startSuspensionEvent

void *volatile	threadHandle = nullptr

ThreadID	threadId = {}

const String	threadName

int	threadPriority = 5

size_t	threadStackSize

Detailed Description

Encapsulates a thread.

Subclasses derive from Thread and implement the run() method, in which they do their business. The thread can then be started with the startThread() method and controlled with various other methods.

This class also contains some thread-related static methods, such as sleep(), yield(), getCurrentThreadId() etc.

See also: CriticalSection, WaitableEvent, Process, ThreadWithProgressWindow, MessageManagerLock

Member Typedef Documentation

◆ ThreadID

typedef void* Thread::ThreadID

A value type used for thread IDs.

See also: getCurrentThreadId(), getThreadId()

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Special realtime audio thread priority.

This priority will create a high-priority thread which is best suited for realtime audio processing.

Currently, this priority is identical to priority 9, except when building for Android with OpenSL support.

In this case, JUCE will ask OpenSL to consturct a super high priority thread specifically for realtime audio processing.

Note that this priority can only be set before the thread has started. Switching to this priority, or from this priority to a different priority, is not supported under Android and will assert.

For best performance this thread should yield at regular intervals and not call any blocking APIS.

See also: startThread, setPriority, sleep, WaitableEvent

Enumerator
realtimeAudioPriority

Constructor & Destructor Documentation

◆ Thread()

Thread::Thread	(	const String &	threadName,
		size_t	threadStackSize = `0`
	)

explicit

Creates a thread.

When first created, the thread is not running. Use the startThread() method to start it.

Parameters

threadName	The name of the thread which typically appears in debug logs and profiles.
threadStackSize	The size of the stack of the thread. If this value is zero then the default stack size of the OS will be used.

◆ ~Thread()

virtual Thread::~Thread ( )

virtual

Destructor.

You must never attempt to delete a Thread object while it's still running - always call stopThread() and make sure your thread has stopped before deleting the object. Failing to do so will throw an assertion, and put you firmly into undefined behaviour territory.

Member Function Documentation

◆ closeThreadHandle()

void Thread::closeThreadHandle ( )

private

◆ currentThreadShouldExit()

static bool Thread::currentThreadShouldExit ( )

static

Checks whether the current thread has been told to stop running.

On the message thread, this will always return false, otherwise it will return threadShouldExit() called on the current thread.

See also: threadShouldExit

◆ getCurrentThread()

static Thread* Thread::getCurrentThread ( )

static

Finds the thread object that is currently running.

Note that the main UI thread (or other non-Juce threads) don't have a Thread object associated with them, so this will return nullptr.

◆ getCurrentThreadId()

Thread::ThreadID Thread::getCurrentThreadId ( )

static

Returns an id that identifies the caller thread.

To find the ID of a particular thread object, use getThreadId().

Returns: a unique identifier that identifies the calling thread.

See also: getThreadId

Referenced by ThreadLocalValue< Type >::get(), and ThreadLocalValue< Type >::releaseCurrentThreadStorage().

◆ getThreadId()

ThreadID Thread::getThreadId ( ) const

inlinenoexcept

Returns the ID of this thread.

That means the ID of this thread object - not of the thread that's calling the method.

This can change when the thread is started and stopped, and will be invalid if the thread's not actually running.

See also: getCurrentThreadId

◆ getThreadName()

const String& Thread::getThreadName ( ) const

inline

Returns the name of the thread.

This is the name that gets set in the constructor.

References JUCE_CALLTYPE.

◆ isThreadRunning()

bool Thread::isThreadRunning ( ) const

Returns true if the thread is currently active.

◆ killThread()

void Thread::killThread ( )

private

References jassertfalse.

◆ launchThread()

void Thread::launchThread ( )

private

References jassertfalse, and threadEntryProc().

◆ notify()

void Thread::notify ( ) const

Wakes up the thread.

If the thread has called the wait() method, this will wake it up.

See also: wait

◆ run()

virtual void Thread::run ( )

pure virtual

Must be implemented to perform the thread's actual code.

Remember that the thread must regularly check the threadShouldExit() method whilst running, and if this returns true it should return from the run() method as soon as possible to avoid being forcibly killed.

See also: threadShouldExit, startThread

Implemented in MidiOutput, and InterprocessConnectionServer.

◆ setAffinityMask()

void Thread::setAffinityMask ( uint32 affinityMask )

Sets the affinity mask for the thread.

This will only have an effect next time the thread is started - i.e. if the thread is already running when called, it'll have no effect.

See also: setCurrentThreadAffinityMask

◆ setCurrentThreadAffinityMask()

void Thread::setCurrentThreadAffinityMask ( uint32 affinityMask )

static

Changes the affinity mask for the caller thread.

This will change the affinity mask for the thread that calls this static method.

See also: setAffinityMask

References juce::ignoreUnused(), and jassertfalse.

◆ setCurrentThreadName()

void Thread::setCurrentThreadName ( const String & newThreadName )

static

Changes the name of the caller thread.

Different OSes may place different length or content limits on this name.

References JUCE_AUTORELEASEPOOL, anonymous_namespace{juce_osx_ObjCHelpers.h}::juceStringToNS(), setName, and String::toRawUTF8().

◆ setCurrentThreadPriority()

static bool Thread::setCurrentThreadPriority ( int priority )

static

Changes the priority of the caller thread.

Similar to setPriority(), but this static method acts on the caller thread. May return false if for some reason the priority can't be changed.

See also: setPriority

◆ setPriority()

bool Thread::setPriority ( int priority )

Changes the thread's priority.

May return false if for some reason the priority can't be changed.

Parameters

priority the new priority, in the range 0 (lowest) to 10 (highest). A priority of 5 is normal.

See also: realtimeAudioPriority

◆ setThreadPriority()

bool Thread::setThreadPriority	(	void *	handle,
		int	priority
	)

staticprivate

References jlimit().

◆ signalThreadShouldExit()

void Thread::signalThreadShouldExit ( )

Sets a flag to tell the thread it should stop.

Calling this means that the threadShouldExit() method will then return true. The thread should be regularly checking this to see whether it should exit.

If your thread makes use of wait(), you might want to call notify() after calling this method, to interrupt any waits that might be in progress, and allow it to reach a point where it can exit.

See also: threadShouldExit; waitForThreadToExit

◆ sleep()

void Thread::sleep ( int milliseconds )

static

Referenced by OpenGLContext::NativeContext::swapBuffers().

◆ startThread() [1/2]

void Thread::startThread ( )

Starts the thread running.

This will cause the thread's run() method to be called by a new thread. If this thread is already running, startThread() won't do anything.

See also: stopThread

◆ startThread() [2/2]

void Thread::startThread ( int priority )

Starts the thread with a given priority.

Launches the thread with a given priority, where 0 = lowest, 10 = highest. If the thread is already running, its priority will be changed.

See also: startThread, setPriority, realtimeAudioPriority

◆ stopThread()

bool Thread::stopThread ( int timeOutMilliseconds )

Attempts to stop the thread running.

This method will cause the threadShouldExit() method to return true and call notify() in case the thread is currently waiting.

Hopefully the thread will then respond to this by exiting cleanly, and the stopThread method will wait for a given time-period for this to happen.

If the thread is stuck and fails to respond after the time-out, it gets forcibly killed, which is a very bad thing to happen, as it could still be holding locks, etc. which are needed by other parts of your program.

Parameters

timeOutMilliseconds The number of milliseconds to wait for the thread to finish before killing it by force. A negative value in here will wait forever.

Returns: true if the thread was cleanly stopped before the timeout, or false if it had to be killed by force.

See also: signalThreadShouldExit, threadShouldExit, waitForThreadToExit, isThreadRunning

◆ threadEntryPoint()

void Thread::threadEntryPoint ( )

private

◆ threadShouldExit()

bool Thread::threadShouldExit ( ) const

inline

Checks whether the thread has been told to stop running.

Threads need to check this regularly, and if it returns true, they should return from their run() method at the first possible opportunity.

See also: signalThreadShouldExit, currentThreadShouldExit

◆ wait()

bool Thread::wait ( int timeOutMilliseconds ) const

Makes the thread wait for a notification.

This puts the thread to sleep until either the timeout period expires, or another thread calls the notify() method to wake it up.

A negative time-out value means that the method will wait indefinitely.

Returns: true if the event has been signalled, false if the timeout expires.

◆ waitForThreadToExit()

bool Thread::waitForThreadToExit ( int timeOutMilliseconds ) const

Waits for the thread to stop.

This will waits until isThreadRunning() is false or until a timeout expires.

Parameters

timeOutMilliseconds the time to wait, in milliseconds. If this value is less than zero, it will wait forever.

Returns: true if the thread exits, or false if the timeout expires first.

◆ yield()

void Thread::yield ( )

static

Yields the calling thread's current time-slot.

Member Data Documentation

◆ affinityMask

uint32 Thread::affinityMask = 0

private

◆ defaultEvent

WaitableEvent Thread::defaultEvent

private

◆ isAndroidRealtimeThread

bool Thread::isAndroidRealtimeThread = false

private

◆ shouldExit

bool volatile Thread::shouldExit = false

private

◆ startStopLock

CriticalSection Thread::startStopLock

private

◆ startSuspensionEvent

WaitableEvent Thread::startSuspensionEvent

private

◆ threadHandle

void* volatile Thread::threadHandle = nullptr

private

◆ threadId

ThreadID Thread::threadId = {}

private

◆ threadName

const String Thread::threadName

private

◆ threadPriority

int Thread::threadPriority = 5

private

◆ threadStackSize

size_t Thread::threadStackSize

private

The documentation for this class was generated from the following files:

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ ThreadID

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ Thread()

◆ ~Thread()

Member Function Documentation

◆ closeThreadHandle()

◆ currentThreadShouldExit()

◆ getCurrentThread()

◆ getCurrentThreadId()

◆ getThreadId()

◆ getThreadName()

◆ isThreadRunning()

◆ killThread()

◆ launchThread()

◆ notify()

◆ run()

◆ setAffinityMask()

◆ setCurrentThreadAffinityMask()

◆ setCurrentThreadName()

◆ setCurrentThreadPriority()

◆ setPriority()

◆ setThreadPriority()

◆ signalThreadShouldExit()

◆ sleep()

◆ startThread() [1/2]

◆ startThread() [2/2]

◆ stopThread()

◆ threadEntryPoint()

◆ threadShouldExit()

◆ wait()

◆ waitForThreadToExit()

◆ yield()

Member Data Documentation

◆ affinityMask

◆ defaultEvent

◆ isAndroidRealtimeThread

◆ shouldExit

◆ startStopLock

◆ startSuspensionEvent

◆ threadHandle

◆ threadId

◆ threadName

◆ threadPriority

◆ threadStackSize