There is no way to wait for completion of started Jobs after calling Stop()

[mrwonko]

When calling Stop() there may still be be Jobs whose Goroutines have been created but were never scheduled. It is therefore impossible to wait for all Jobs to complete, because some may not yet be running, making it impossible to track them.

The right place for adding to a sync.WaitGroup would be in Cron:run() right before go c.runWithRecovery(e.Job). You could then add a new Cron:Wait() function for waiting for jobs to finish after calling Stop().

[robfig]

I agree, this is very hard for users to do without support from cron. I will implement this.

[robfig]

This is now implemented. Have a look at the referenced commit for how to use it. Thanks
15ec73d

[mrwonko]

Great! Just keep the peculiarities of WaitGroup.Add in mind:

Note that calls with a positive delta that occur when the counter is zero must happen before a Wait.

So anybody wishing to re-use a Cron object now has to wait for the context returned by Stop() to complete before calling Run() again, or else there's a risk of the Add() call happening concurrently with Wait().