TThread¶

Abstract Thread class.

Declaration¶

Source position: classesh.inc line 2392

type

  TThread = class
  public
    TSystemTimes = record
      IdleTime: QWord;
      UserTime: QWord;
      KernelTime: QWord;
      NiceTime: QWord;
    end;
    constructor Create;
    destructor Destroy;
    class function CreateAnonymousThread(aProc: TProcedure) : TThread;
    class function CreateAnonymousThread(aProc: TThreadMethod) : TThread;
    class procedure NameThreadForDebugging(aThreadName: UnicodeString; 
                                      aThreadID: TThreadID=TThreadID(- 1));
    class procedure NameThreadForDebugging(aThreadName: AnsiString; 
                                      aThreadID: TThreadID=TThreadID(- 1));
    class procedure SetReturnValue;
    class function CheckTerminated : Boolean;
    class procedure RemoveQueuedEvents(aThread: TThread; 
                                  aMethod: TThreadMethod);
    class procedure RemoveQueuedEvents(aMethod: TThreadMethod);
    class procedure RemoveQueuedEvents(aThread: TThread);
    class procedure SpinWait;
    class procedure Sleep;
    class procedure Yield;
    class function GetSystemTimes : Boolean;
    class function GetCPUUsage : Integer;
    class function GetTickCount : LongWord;
    class function GetTickCount64 : QWord;
    class function ExecuteInThread(AMethod: TThreadExecuteHandler; 
                              AOnTerminate: TNotifyEvent=Nil) : TThread; overload;
    class function ExecuteInThread(AMethod: TThreadExecuteStatusHandler; 
                              AOnStatus: TThreadStatusNotifyEvent; 
                              AOnTerminate: TNotifyEvent=Nil) : TThread; overload;
    class function ExecuteInThread(AMethod: TThreadExecuteCallBack; 
                              AData: Pointer=Nil; 
                              AOnTerminate: TNotifyCallBack=Nil)
                               : TThread; overload;
    class function ExecuteInThread(AMethod: TThreadExecuteStatusCallBack; 
                              AOnStatus: TThreadStatusNotifyCallBack; 
                              AData: Pointer=Nil; 
                              AOnTerminate: TNotifyCallBack=Nil)
                               : TThread; overload;
    procedure AfterConstruction;
    procedure Start;
    procedure Resume;
    procedure Suspend;
    procedure Terminate;
    function WaitFor : Integer;
    class function CurrentIsMain : Boolean;
    class property CurrentThread: TThread; {r}
    class property Current: TThread; {r}
    class property ProcessorCount: LongWord; {r}
    class property IsSingleProcessor: Boolean; {r}
    property FreeOnTerminate: Boolean; {rw}
    property Handle: TThreadHandle; {r}
    property ExternalThread: Boolean; {r}
    property Priority: TThreadPriority; {rw}
    property Suspended: Boolean; {rw}
    property Finished: Boolean; {r}
    property ThreadID: TThreadID; {r}
    property OnTerminate: TNotifyEvent; {rw}
    property FatalException: TObject; {r}
  end;

Inheritance¶

Description¶

The TThread class encapsulates the native thread support of the operating system. To create a thread, declare a descendant of the TThread object and override the Execute method. In this method, the tthread's code should be executed. To run a thread, create an instance of the tthread descendant, and call it's execute method.

It is also possible to simply execute a method or static procedure in a thread using the TThread.ExecuteInThread class method.

Properties¶

Member	Visibility	Description
Current read only	public
CurrentThread read only	public	Return current thread instance.
ExternalThread read only	public	Is the thread instance an external thread ?
FatalException read only	public	Exception that occurred during thread execution.
Finished read only	public	Has the thread finished executing.
FreeOnTerminate	public	Indicates whether the thread should free itself when it stops executing.
Handle read only	public	Returns the thread handle.
IsSingleProcessor read only	public	Is the current system single processor or not.
Priority	public	Returns the thread priority.
ProcessorCount read only	public	Return the processor count for this system.
Suspended	public	Indicates whether the thread is suspended.
ThreadID read only	public	Returns the thread ID.

Methods¶

Member	Visibility	Description
AfterConstruction	public	Code to be executed after construction but before execute.
CheckTerminated	public	Check if the current thread has finished executing.
Create	public	Creates a new thread.
CreateAnonymousThread	public	Execute code in an anonymous thread.
CurrentIsMain	public
Destroy	public	Destroys the thread object.
Execute	protected	Execute method. Must be overridden in a descendant thread.
ExecuteInThread	public	Execute a method or static procedure in a thread.
ForceQueue	protected	Always queue a method for execution in the main thread.
GetCPUUsage	public
GetSystemTimes	public	Return CPU stats.
GetTickCount	public	Return tick count (32-bit).
GetTickCount64	public	Return tick count (64-bit).
NameThreadForDebugging	public	Set a thread name.
Queue	protected	Queue a method for execution in the main thread.
RemoveQueuedEvents	public	Remove methods scheduled for execution from queue.
Resume	public	Resumes the thread's execution. Deprecated, see TThread.Start.
SetReturnValue	public	Set return value of a thread.
Sleep	public	Prevent thread execution.
SpinWait	public	Prevent thread execution in a spin-wait loop.
Start	public	Starts a thread that was created in a suspended state.
Suspend	public	Suspends the thread's execution.
Synchronize	protected	Synchronizes the thread by executing the method in the main thread.
Terminate	public	Signals the thread it should terminate.
WaitFor	public	Waits for the thread to terminate and returns the exit status.
Yield	public	Yield execution to other threads.

Events¶

Member	Visibility	Description
OnTerminate	public	Event called when the thread terminates.

Name	Description
EThread	Thread error exception.
TThread.Execute	Execute method. Must be overridden in a descendant thread.
TThread.ExecuteInThread	Execute a method or static procedure in a thread.