Run unlimited iterations of the main loop object until the main loop's
quit() routine is called. Returns a negative value on error. Optionally return
the return value as specified with the main loop's quit() routine in the integer
variable retval points to.
Run unlimited iterations of the main loop object until the main loop's quit() routine is called. Returns a negative value on error. Optionally return the return value as specified with the main loop's quit() routine in the integer variable retval points to.