On Thu, 12 Feb 2015, Dave Mielke wrote: > [quoted lines by Alan Stern on 2015/02/12 at 10:10 -0500] > > >Not to me. The purpose of signalfd is to report pending signals. > >Closing or opening a file descriptor shouldn't change the set of > >pending signals. > > Once the last signalfd file descriptor for a given signal is closed - in our > case, that's only one of them - shouldn't the handling revert to the default > for that signal? Isn't it wrong that, when there are no signalfd file > descriptors open for a given signal, the signal still seems to stay pending > within the signalfd mechanism? Doesn't your program mask those signals before submitting URBs? It must; otherwise the completion signals would be delivered to the program in the normal way via a signal handler instead of being reported via signalfd. The signals remain masked even after the file descriptor is closed. Opening or closing a signalfd descriptor doesn't change the set of masked signals -- not according to the man page entry, anyway. Signals don't remain pending within the signalfd mechanism; they just remain pending. They operate more or less independently of signalfd. The only purpose of signalfd is to _report_ pending signals. It doesn't store them or anything like that. The only interaction is this: When the program reads from signalfd that a signal is pending, the signal then becomes unpending (just as if the program's signal handler had run). Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
