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POPython separate threads are killing the whole program
 

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  1. POPython separate threads are killing the whole program
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    <p>So I wrote this script:</p> <pre><code>def schedule_setup(): # KILL OLD THREADS SHOULD THEY EXIST global active active = False time.sleep(3) active = True global threadlist threadlist = [] try: sql = "SELECT TIME_TO_RUN FROM time_table" cursor.execute(sql) results = cursor.fetchall() for row in results: #row[0].strftime('%H:%M') t = threading.Thread(target=th,args=(row[0].strftime('%H:%M'),)) t.start() threadlist.append(t) # JOIN all threads to main memory #for count in threadlist: #count.join() sql = "UPDATE motor SET UPDATE_SCHEDULE = 0" try: cursor.execute(sql) # commit the changes in database db.commit() except: # Rollback in case there is any error print "no worky" db.rollback() except: print "Error: UNABLE TO GET TABLE DATA" </code></pre> <p>It takes times setup on sql and creates a scheduled event to do an action. I put in the beginning the thread "killer" for all active threads so that if I ever call this thread again because times have been updated it can kill old ones and replace them with the new. It all works how I want it to, but as soon as the action is called the whole program crashes... here is the code it calls:</p> <pre><code>def th(run_time): global active schedule.every().day.at(run_time).do(run_motor) while active == True: schedule.run_pending() time.sleep(1) </code></pre> <p>see how the thread checks every second? So threads are killed when I try to create new ones, but when "run_motor" gets called, afterwords the main program that is supposed to loop indefinitely crashes and sometimes other threads are still going so it is all very strange to me.</p>
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    1. USCraig Travis
    1. USCraig Travis
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    1. COWhat does "crashes" mean, exactly? Do you get an error message? Do you get a traceback? If so, spell them out for us.
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      1. USTim Peters
    2. COBTW, since you say sometimes threads are still going, it's certain that your `time.sleep(3)` isn't long enough for all threads to end. There's not enough info here to guess why, though. You should be `.join()`ing threads if you want to be sure they're done - sleeping is never a reliable alternative.
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      1. USTim Peters
    3. COWould also help ;-) if you fixed the indentation in the code - unclear where, for example, `schedule_setup()` ends, since everything is flush to the left border.
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      1. USTim Peters
 

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