On 18/03/15 18:28, Doug Basberg wrote:
I do real-time controls programming and I control a relay in a python program that must be turned off before the program ends.
You don't say what your environment is but you should be aware that Python is not really a suitable tool for real time programming, especially if it safety critical. The same applies to most(all?) scripting languages and especially if running on a time sharing OS like Unix or windows. If your code is not truly real-time or the device is not safety critical you may get away with it. But if you are likely to get sued for loss of life or major damage consider your options. That having been said there are several things you can do to safeguard yourself. Others have mentioned the exit hooks in the sys module, You can also try wrapping your entire main program in a try/finally. You could also monitor the interpreter in an external program that turns off your device directly if the interpreter fails. But none of these can be guaranteed to happen in real time indeed, the last option can be guaranteed not to be... -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
