pause/contiune Workerfunc in Thread

Boris1980

Hello Guys,

i have a thread which calls a method in a cycle intervall:

void run()

{
	while (true)
		{
			_holdOnMutex.lock();
			
			if(!_holdOn)
			{
			doJob() ; /* my function which have to complete and has to blocks the thread_pause method */
			}

			_holdOnMutex.unlock();

			QThread::msleep(20);
		}
}

now i want to pause and continue this thread in a conistent way, an wrote two mehtods:

QMutex _holdOnMutex;
bool _holdOn;
void pause_Thread()
{
	_holdOnMutex.lock();
	_holdOn = true;
	_holdOnMutex.unlock();
}
void continue_Thread()
{
	_holdOnMutex.lock();
	_holdOn = false;
	_holdOnMutex.unlock();
}

is this a good approch, or there a better solution for my case?

Thank for your suggestions...:)

SGaist

Hi,

QWaitCondition might be of interest.

enjoysmath

I don't know if this is any better. But here's my pauseable_thread.py:

from PyQt5.QtCore import QThread, QMutex, QWaitCondition

class PauseableThread(QThread):  #(QThread):
    def __init__(self):
        super().__init__()
        self._pauseMutex = QMutex()
        self._pauseCond = QWaitCondition()
        self._paused = False
    
    def paused(self):
        return self._paused
    
    def pause(self):
        if self.isRunning() and not self._paused:
            self._pauseMutex.lock()
            self._paused = True
            self._pauseMutex.unlock()
        
    def resume(self):
        if self.isRunning() and self._paused:
            self._pauseMutex.lock()
            self._paused = False
            self._pauseMutex.unlock()
            self._pauseCond.wakeAll()
    
    def checkPause(self):
        self._pauseMutex.lock()
        if self._paused:
            self._pauseCond.wait(self._pauseMutex)
        self._pauseMutex.unlock()

You then inherit from this class and call self.checkPause() in your main thread loop or anywhere you deem appropriate.

Boris1980

Thank for your replay, and thank for your QWaitCondition suggestion, but what i dont understand the mechansi in your pausable trhead class:

When call the pause method ,the paused flag is true,

the checkpause method rrun to the wait condion ,

the pausemutex is locked

how can the resume mothode execute, if the pausemutex is locked!?