Orocos Real-Time Toolkit  2.6.0
Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | Friends
RTT::os::Thread Class Reference

A Thread object executes user code in its own thread. More...

#include <rtt/os/Thread.hpp>

Inheritance diagram for RTT::os::Thread:
RTT::os::ThreadInterface RTT::Activity RTT::extras::TimerThread RTT::corba::CorbaDispatcher RTT::corba::OrbRunner RTT::extras::FileDescriptorActivity RTT::extras::IRQActivity RTT::mqueue::Dispatcher RTT::extras::SimulationThread

List of all members.

Public Member Functions

 Thread (int scheduler, int priority, double period, unsigned cpu_affinity, const std::string &name)
 Create a Thread with a given scheduler type, priority and a name.
virtual bool start ()
 Start the Thread.
virtual bool stop ()
 Stop the Thread.
bool setPeriod (Seconds s)
 Set the periodicity in Seconds.
bool setPeriod (secs s, nsecs ns)
 Set the periodicity of this thread (seconds, nanoseconds)
bool setPeriod (TIME_SPEC p)
 Set the periodicity of this thread.
void getPeriod (secs &s, nsecs &ns) const
 Get the periodicity of this thread (seconds, nanoseconds)
virtual Seconds getPeriod () const
 Get the periodicity in Seconds.
virtual nsecs getPeriodNS () const
 Get the periodicity in nanoseconds.
virtual bool isPeriodic () const
virtual bool isRunning () const
 Returns whether the thread is running.
virtual bool isActive () const
 Returns whether the thread is active.
virtual const char * getName () const
 Read the name of this task.
virtual RTOS_TASK * getTask ()
 Get the RTOS_TASK pointer.
virtual const RTOS_TASK * getTask () const
 const version of the above.
virtual bool setScheduler (int sched_type)
 Change the scheduler policy in which this thread runs.
virtual int getScheduler () const
 Get the scheduler policy in which this thread runs.
virtual bool setPriority (int priority)
 Set the priority of this Thread.
virtual int getPriority () const
 The priority of this Thread.
virtual unsigned int getPid () const
 Returns the Process or Thread ID of this thread, as assigned by the Operating System.
virtual bool setCpuAffinity (unsigned cpu_affinity)
 Set cpu affinity for this thread The cpu affinity of the thread (.
virtual unsigned getCpuAffinity () const
virtual void yield ()
 Yields (put to the back of the scheduler queue) the calling thread.
virtual void setMaxOverrun (int m)
virtual int getMaxOverrun () const
virtual void setWaitPeriodPolicy (int p)
 Set the wait policy of a periodic thread.
unsigned int threadNumber () const
 The unique thread number (within the same process).
bool isSelf () const

Static Public Member Functions

static void setStackSize (unsigned int ssize)
 Sets the stack size of the threads to be created.

Protected Member Functions

void terminate ()
 Exit and destroy the thread.
void emergencyStop ()
virtual void step ()
virtual void loop ()
virtual bool breakLoop ()
virtual bool initialize ()
virtual void finalize ()

Protected Attributes

int threadnb
 Threads are given an unique number, which follows thread creation order.

Friends

void * thread_function (void *t)

Detailed Description

A Thread object executes user code in its own thread.

If the underlying OS supports it, both period and priority can be changed after creation. When the period is 0, the loop() function is executed, when the period is greater than 0, the step() function is executed. Note: if the user does not implement loop(), it will call step() by default.

The main functions to implement are initialize(), step()/loop() and finalize(). initialize() is called when start() is called, and before the first step()/loop() and finalize() is called when stop() is called after the last step()/loop() returns.

behavior

When a period is set, step() is executed from the moment start() is called, and afterwards according to it's period. When stop() is called, it waits for the step() function to return and then stops the periodic execution.

Step() overruns are detected and the threshold to 'emergency stop' the thread can be set by setMaxOverrun(). Overruns must be accumulated 'on average' to trigger this behavior: one not overrunning step() compensates for one overrunning step().

periodic behaviour

The first invocation of start() invokes the initialize() function and runs the loop() method in the thread. When loop() returns the thread waits for another start() to execute loop() again. In that case, initialize() is not executed.

When stop() is called and the thread is still executing loop() and breakLoop() returns true (not the default), the stop() function succeeds and the finalize() method is called by stop(). If the thread was not executing loop(), stop will always call finalize() and return success.

The user must provide an implementation of breakLoop() returning true to make stop() work while loop() is being executed. stop() will fail and not execute finalize() if the thread executes loop() and breakLoop() is not reimplemented to return true.

, priorities, schedulers and stack sizes

These four parameters are the parameters that users wish to set for every thread created. All but stack size can be modified after creation, and if the OS permits it, modified even when the thread is using user code. All these parameters are passed to the underlying OS unmodified. In case an incorrect combination is made, the change may be rejected or adjusted to a close or safe value.

See also:
setPeriod, setScheduler, setPriority, setStackSize

Definition at line 109 of file Thread.hpp.


Constructor & Destructor Documentation

RTT::os::Thread::Thread ( int  scheduler,
int  priority,
double  period,
unsigned  cpu_affinity,
const std::string &  name 
)

Create a Thread with a given scheduler type, priority and a name.

Parameters:
schedulerThe scheduler, one of ORO_SCHED_RT or ORO_SCHED_OTHER.
priorityThe priority of the thread, this is interpreted by your RTOS.
periodThe period in seconds (eg 0.001) of the thread, or zero if not periodic.
cpu_affinityThe cpu affinity of the thread, this is interpreted by your RTOS.
nameThe name of the Thread. May be used by your OS to identify the thread. the thread's own virtual functions are executed.

Definition at line 238 of file Thread.cpp.


Member Function Documentation

bool RTT::os::Thread::breakLoop ( ) [protected, virtual]
void RTT::os::Thread::finalize ( ) [protected, virtual]
unsigned RTT::os::Thread::getCpuAffinity ( ) const [virtual]
Returns:
the cpu affinity (
See also:
rtos_task_set_cpu_affinity)

Reimplemented in RTT::Activity.

Definition at line 593 of file Thread.cpp.

References RTT::os::rtos_task_get_cpu_affinity().

double RTT::os::Thread::getPeriod ( ) const [virtual]

Get the periodicity in Seconds.

Return zero if non periodic.

Implements RTT::os::ThreadInterface.

Reimplemented in RTT::Activity.

Definition at line 578 of file Thread.cpp.

Referenced by RTT::extras::SimulationThread::run(), RTT::extras::SimulationThread::SimulationThread(), RTT::extras::SimulationThread::step(), and stop().

nsecs RTT::os::Thread::getPeriodNS ( ) const [virtual]

Get the periodicity in nanoseconds.

Return zero if non periodic.

Implements RTT::os::ThreadInterface.

Definition at line 583 of file Thread.cpp.

unsigned int RTT::os::Thread::getPid ( ) const [virtual]

Returns the Process or Thread ID of this thread, as assigned by the Operating System.

This function tries to return the Thread ID, if the OS supports it, otherwise it returns the process ID. If that is not available either, zero is returned. On Linux systems for example, the Thread ID of the main thread is equal to the Process ID. The Thread ID of every newly created thread is different from the Process ID (and unique).

Implements RTT::os::ThreadInterface.

Definition at line 598 of file Thread.cpp.

References RTT::os::rtos_task_get_pid().

int RTT::os::Thread::getPriority ( ) const [virtual]

The priority of this Thread.

Returns:
The priority given upon construction of this thread or set with setPriority. The returned number has to be interpreted in the current OS scheduler.
See also:
setScheduler

Implements RTT::os::ThreadInterface.

Definition at line 573 of file Thread.cpp.

References RTT::os::rtos_task_get_priority().

Referenced by RTT::extras::SimulationThread::SimulationThread().

int RTT::os::Thread::getScheduler ( ) const [virtual]

Get the scheduler policy in which this thread runs.

Returns:
An OS-specific value which represents the used scheduler.
See also:
setScheduler

Implements RTT::os::ThreadInterface.

Definition at line 475 of file Thread.cpp.

References RTT::os::rtos_task_get_scheduler().

Referenced by setScheduler().

virtual RTOS_TASK* RTT::os::Thread::getTask ( ) [inline, virtual]

Get the RTOS_TASK pointer.

Note:
Using this function leads to non-portable code. It is here for users which wish to tweak OS specific thread settings.

Implements RTT::os::ThreadInterface.

Definition at line 174 of file Thread.hpp.

Referenced by RTT::os::thread_function().

bool RTT::os::Thread::initialize ( ) [protected, virtual]
bool RTT::os::Thread::isActive ( ) const [virtual]

Returns whether the thread is active.

A thread is active between the invocation of start() and the invocation of stop().

Implements RTT::os::ThreadInterface.

Reimplemented in RTT::Activity.

Definition at line 451 of file Thread.cpp.

Referenced by start().

bool RTT::os::Thread::isRunning ( ) const [virtual]

Returns whether the thread is running.

A thread is running if it is executing its loop() function or in the process of periodically calling step(). Hence for periodic threads, isRunning() == isActive() while for non-periodic threads, isRunning() is only true if isActive() and it is executing loop().

Implements RTT::os::ThreadInterface.

Reimplemented in RTT::Activity, RTT::extras::FileDescriptorActivity, and RTT::extras::SimulationThread.

Definition at line 446 of file Thread.cpp.

void RTT::os::Thread::loop ( ) [protected, virtual]
bool RTT::os::Thread::setCpuAffinity ( unsigned  cpu_affinity) [virtual]

Set cpu affinity for this thread The cpu affinity of the thread (.

See also:
rtos_task_set_cpu_affinity).
Returns:
true if the mask has been applied

Reimplemented in RTT::Activity.

Definition at line 588 of file Thread.cpp.

References RTT::os::rtos_task_set_cpu_affinity().

bool RTT::os::Thread::setPeriod ( Seconds  new_period) [virtual]

Set the periodicity in Seconds.

Parameters:
new_periodA positive number expressing the period
Returns:
true if it was accepted, false otherwise.

Implements RTT::os::ThreadInterface.

Reimplemented in RTT::Activity.

Definition at line 523 of file Thread.cpp.

Referenced by setPeriod().

bool RTT::os::Thread::setPriority ( int  priority) [virtual]

Set the priority of this Thread.

Parameters:
priorityThe priority given upon construction of this thread. It has to be interpreted in the current OS scheduler.
See also:
setScheduler

Implements RTT::os::ThreadInterface.

Definition at line 563 of file Thread.cpp.

References RTT::os::rtos_task_set_priority().

bool RTT::os::Thread::setScheduler ( int  sched_type) [virtual]

Change the scheduler policy in which this thread runs.

Parameters:
sched_typeAn OS-specific value which selects a scheduler. Orocos requires that these two values are available:
  • ORO_SCHED_RT: Hint the OS that this thread should be scheduled as a priority or real-time process.
  • ORO_SCHED_OTHER: Hint the OS that this thread should not be scheduled as a priority or real-time process.

Your OS can in addition provide other sched_type's which map more naturally to the schedulers present. If your OS does not make a distinction between real-time and other, both values may map to the same scheduler type.

Returns:
true if the change could be made.

Implements RTT::os::ThreadInterface.

Definition at line 456 of file Thread.cpp.

References RTT::os::CheckScheduler(), getScheduler(), RTT::os::rtos_task_get_name(), and RTT::os::rtos_task_set_scheduler().

Referenced by RTT::extras::SimulationThread::SimulationThread().

void RTT::os::Thread::setStackSize ( unsigned int  ssize) [static]

Sets the stack size of the threads to be created.

This value is suggestive and may be altered or ignored by your operating system. Use zero to use the system's default.

Parameters:
ssizethe size of the stack in bytes

Definition at line 73 of file Thread.cpp.

void RTT::os::Thread::setWaitPeriodPolicy ( int  p) [virtual]

Set the wait policy of a periodic thread.

Parameters:
Thewait policy between ORO_WAIT_ABS (absolute wait) and ORO_WAIT_REL (relative wait)

Implements RTT::os::ThreadInterface.

Definition at line 634 of file Thread.cpp.

References RTT::os::rtos_task_set_wait_period_policy().

bool RTT::os::Thread::start ( ) [virtual]

Start the Thread.

Postcondition:
initialize() is called first
The Thread is running
Returns:
true if the function did succeed. false otherwise.

Implements RTT::os::ThreadInterface.

Reimplemented in RTT::extras::FileDescriptorActivity, RTT::Activity, RTT::extras::IRQActivity, and RTT::extras::SimulationThread.

Definition at line 339 of file Thread.cpp.

References initialize(), isActive(), and RTT::os::rtos_task_make_periodic().

void RTT::os::Thread::step ( ) [protected, virtual]
bool RTT::os::Thread::stop ( ) [virtual]

Stop the Thread.

Postcondition:
The Thread is no longer being run
finalize() is called when the Thread is stopped.
Returns:
true if the function did succeed. false otherwise.

Implements RTT::os::ThreadInterface.

Reimplemented in RTT::extras::FileDescriptorActivity, and RTT::Activity.

Definition at line 404 of file Thread.cpp.

References breakLoop(), finalize(), getName(), getPeriod(), RTT::os::MutexTimedLock::isSuccessful(), and RTT::os::rtos_task_make_periodic().

Referenced by RTT::extras::SimulationThread::step(), RTT::extras::SimulationThread::~SimulationThread(), and RTT::extras::TimerThread::~TimerThread().

void RTT::os::Thread::terminate ( ) [protected]

Exit and destroy the thread.

Precondition:
this is only called from within the destructor.
Postcondition:
the thread does no longer exist.

Definition at line 608 of file Thread.cpp.

References RTT::os::rtos_task_delete().


Friends And Related Function Documentation

void* thread_function ( void *  t) [friend]

This is one time initialisation

The real task starts here.

Definition at line 75 of file Thread.cpp.


Member Data Documentation

int RTT::os::ThreadInterface::threadnb [protected, inherited]

Threads are given an unique number, which follows thread creation order.

See also:
os::threads

Definition at line 223 of file ThreadInterface.hpp.


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