| … | |
… | |
| 1755 | |
1755 | |
| 1756 | If the event loop is suspended for a long time, you can also force an |
1756 | If the event loop is suspended for a long time, you can also force an |
| 1757 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
1757 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
| 1758 | ()>. |
1758 | ()>. |
| 1759 | |
1759 | |
|
|
1760 | =head3 The special problems of suspended animation |
|
|
1761 | |
|
|
1762 | When you leave the server world it is quite customary to hit machines that |
|
|
1763 | can suspend/hibernate - what happens to the clocks during such a suspend? |
|
|
1764 | |
|
|
1765 | Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes |
|
|
1766 | all processes, while the clocks (C<times>, C<CLOCK_MONOTONIC>) continue |
|
|
1767 | to run until the system is suspended, but they will not advance while the |
|
|
1768 | system is suspended. That means, on resume, it will be as if the program |
|
|
1769 | was frozen for a few seconds, but the suspend time will not be counted |
|
|
1770 | towards C<ev_timer> when a monotonic clock source is used. The real time |
|
|
1771 | clock advanced as expected, but if it is used as sole clocksource, then a |
|
|
1772 | long suspend would be detected as a time jump by libev, and timers would |
|
|
1773 | be adjusted accordingly. |
|
|
1774 | |
|
|
1775 | I would not be surprised to see different behaviour in different between |
|
|
1776 | operating systems, OS versions or even different hardware. |
|
|
1777 | |
|
|
1778 | The other form of suspend (job control, or sending a SIGSTOP) will see a |
|
|
1779 | time jump in the monotonic clocks and the realtime clock. If the program |
|
|
1780 | is suspended for a very long time, and monotonic clock sources are in use, |
|
|
1781 | then you can expect C<ev_timer>s to expire as the full suspension time |
|
|
1782 | will be counted towards the timers. When no monotonic clock source is in |
|
|
1783 | use, then libev will again assume a timejump and adjust accordingly. |
|
|
1784 | |
|
|
1785 | It might be beneficial for this latter case to call C<ev_suspend> |
|
|
1786 | and C<ev_resume> in code that handles C<SIGTSTP>, to at least get |
|
|
1787 | deterministic behaviour in this case (you can do nothing against |
|
|
1788 | C<SIGSTOP>). |
|
|
1789 | |
| 1760 | =head3 Watcher-Specific Functions and Data Members |
1790 | =head3 Watcher-Specific Functions and Data Members |
| 1761 | |
1791 | |
| 1762 | =over 4 |
1792 | =over 4 |
| 1763 | |
1793 | |
| 1764 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1794 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
| … | |
… | |
| 1789 | If the timer is repeating, either start it if necessary (with the |
1819 | If the timer is repeating, either start it if necessary (with the |
| 1790 | C<repeat> value), or reset the running timer to the C<repeat> value. |
1820 | C<repeat> value), or reset the running timer to the C<repeat> value. |
| 1791 | |
1821 | |
| 1792 | This sounds a bit complicated, see L<Be smart about timeouts>, above, for a |
1822 | This sounds a bit complicated, see L<Be smart about timeouts>, above, for a |
| 1793 | usage example. |
1823 | usage example. |
|
|
1824 | |
|
|
1825 | =item ev_timer_remaining (loop, ev_timer *) |
|
|
1826 | |
|
|
1827 | Returns the remaining time until a timer fires. If the timer is active, |
|
|
1828 | then this time is relative to the current event loop time, otherwise it's |
|
|
1829 | the timeout value currently configured. |
|
|
1830 | |
|
|
1831 | That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns |
|
|
1832 | C<5>. When the timer is started and one second passes, C<ev_timer_remain> |
|
|
1833 | will return C<4>. When the timer expires and is restarted, it will return |
|
|
1834 | roughly C<7> (likely slightly less as callback invocation takes some time, |
|
|
1835 | too), and so on. |
| 1794 | |
1836 | |
| 1795 | =item ev_tstamp repeat [read-write] |
1837 | =item ev_tstamp repeat [read-write] |
| 1796 | |
1838 | |
| 1797 | The current C<repeat> value. Will be used each time the watcher times out |
1839 | The current C<repeat> value. Will be used each time the watcher times out |
| 1798 | or C<ev_timer_again> is called, and determines the next timeout (if any), |
1840 | or C<ev_timer_again> is called, and determines the next timeout (if any), |
