Inconsistent running of subprocess

Darby

Hi all,

I have noticed that in a program I am running (that was written pre 3.1), it is inconsistently calling a subroutine. Basically, if one object is picked, it should release 3 pieces of food from a dispenser (this is the .vbs file). However, it only did that on 4 of 10 trials. On the remaining 6 trials, it only release twice.

I know there have been some changes in the latest update. So, I tried changing all the time functions to clock functions, but with the same result. Can anyone help?

Thanks

if x > (self.get('xHigh') - maxClickErr) and x < (self.get('xHigh') + maxClickErr) and y > (self.get('yHigh') - maxClickErr) and y < (self.get('yHigh') + maxClickErr): 
    my_canvas.circle(self.get('xLow'), self.get('yLow'), 120, fill=True, color='black')
    my_canvas.show()
    exp.sound = pygame.mixer.Sound(high_path)
    exp.sound.play()
    time.sleep(.70)
    subprocess.call("wscript.exe c:\invis.vbs")     
    time.sleep(.70)
    subprocess.call("wscript.exe c:\invis.vbs")
    time.sleep(.70)
    subprocess.call("wscript.exe c:\invis.vbs")
    time.sleep(.70)
    high +=1
    break

sebastiaan

Hi,

Subprocesses are always tricky. Here's what I would do:

• Pass the command as a list: ["wscript.exe", "c:\invis.vbs"] instead of as a single str. I'm surprised that it even works like this at all.
• Use subprocess.check_call() instead of subprocess.call() to check whether the processes ended correctly. check_call() will raise a CalledProcessError when it doesn't, whereas call() will fail silently.
• Increase the delay between the subsequent calls.

See also:

• https://docs.python.org/2/library/subprocess.html

Cheers!
Sebastiaan

Darby

Thanks! That works perfectly.