… | |
… | |
260 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
260 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
261 | |
261 | |
262 | If you don't know what event loop to use, use the one returned from this |
262 | If you don't know what event loop to use, use the one returned from this |
263 | function. |
263 | function. |
264 | |
264 | |
|
|
265 | The default loop is the only loop that can handle C<ev_signal> and |
|
|
266 | C<ev_child> watchers, and to do this, it always registers a handler |
|
|
267 | for C<SIGCHLD>. If this is a problem for your app you can either |
|
|
268 | create a dynamic loop with C<ev_loop_new> that doesn't do that, or you |
|
|
269 | can simply overwrite the C<SIGCHLD> signal handler I<after> calling |
|
|
270 | C<ev_default_init>. |
|
|
271 | |
265 | The flags argument can be used to specify special behaviour or specific |
272 | The flags argument can be used to specify special behaviour or specific |
266 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
273 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
267 | |
274 | |
268 | The following flags are supported: |
275 | The following flags are supported: |
269 | |
276 | |
… | |
… | |
403 | While this backend scales well, it requires one system call per active |
410 | While this backend scales well, it requires one system call per active |
404 | file descriptor per loop iteration. For small and medium numbers of file |
411 | file descriptor per loop iteration. For small and medium numbers of file |
405 | descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend |
412 | descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend |
406 | might perform better. |
413 | might perform better. |
407 | |
414 | |
|
|
415 | On the positive side, ignoring the spurious readyness notifications, this |
|
|
416 | backend actually performed to specification in all tests and is fully |
|
|
417 | embeddable, which is a rare feat among the OS-specific backends. |
|
|
418 | |
408 | =item C<EVBACKEND_ALL> |
419 | =item C<EVBACKEND_ALL> |
409 | |
420 | |
410 | Try all backends (even potentially broken ones that wouldn't be tried |
421 | Try all backends (even potentially broken ones that wouldn't be tried |
411 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
422 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
412 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
423 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
… | |
… | |
414 | It is definitely not recommended to use this flag. |
425 | It is definitely not recommended to use this flag. |
415 | |
426 | |
416 | =back |
427 | =back |
417 | |
428 | |
418 | If one or more of these are ored into the flags value, then only these |
429 | If one or more of these are ored into the flags value, then only these |
419 | backends will be tried (in the reverse order as given here). If none are |
430 | backends will be tried (in the reverse order as listed here). If none are |
420 | specified, most compiled-in backend will be tried, usually in reverse |
431 | specified, all backends in C<ev_recommended_backends ()> will be tried. |
421 | order of their flag values :) |
|
|
422 | |
432 | |
423 | The most typical usage is like this: |
433 | The most typical usage is like this: |
424 | |
434 | |
425 | if (!ev_default_loop (0)) |
435 | if (!ev_default_loop (0)) |
426 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
436 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
… | |
… | |
473 | Like C<ev_default_destroy>, but destroys an event loop created by an |
483 | Like C<ev_default_destroy>, but destroys an event loop created by an |
474 | earlier call to C<ev_loop_new>. |
484 | earlier call to C<ev_loop_new>. |
475 | |
485 | |
476 | =item ev_default_fork () |
486 | =item ev_default_fork () |
477 | |
487 | |
|
|
488 | This function sets a flag that causes subsequent C<ev_loop> iterations |
478 | This function reinitialises the kernel state for backends that have |
489 | to reinitialise the kernel state for backends that have one. Despite the |
479 | one. Despite the name, you can call it anytime, but it makes most sense |
490 | name, you can call it anytime, but it makes most sense after forking, in |
480 | after forking, in either the parent or child process (or both, but that |
491 | the child process (or both child and parent, but that again makes little |
481 | again makes little sense). |
492 | sense). You I<must> call it in the child before using any of the libev |
|
|
493 | functions, and it will only take effect at the next C<ev_loop> iteration. |
482 | |
494 | |
483 | You I<must> call this function in the child process after forking if and |
495 | On the other hand, you only need to call this function in the child |
484 | only if you want to use the event library in both processes. If you just |
496 | process if and only if you want to use the event library in the child. If |
485 | fork+exec, you don't have to call it. |
497 | you just fork+exec, you don't have to call it at all. |
486 | |
498 | |
487 | The function itself is quite fast and it's usually not a problem to call |
499 | The function itself is quite fast and it's usually not a problem to call |
488 | it just in case after a fork. To make this easy, the function will fit in |
500 | it just in case after a fork. To make this easy, the function will fit in |
489 | quite nicely into a call to C<pthread_atfork>: |
501 | quite nicely into a call to C<pthread_atfork>: |
490 | |
502 | |
491 | pthread_atfork (0, 0, ev_default_fork); |
503 | pthread_atfork (0, 0, ev_default_fork); |
492 | |
504 | |
493 | At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use |
|
|
494 | without calling this function, so if you force one of those backends you |
|
|
495 | do not need to care. |
|
|
496 | |
|
|
497 | =item ev_loop_fork (loop) |
505 | =item ev_loop_fork (loop) |
498 | |
506 | |
499 | Like C<ev_default_fork>, but acts on an event loop created by |
507 | Like C<ev_default_fork>, but acts on an event loop created by |
500 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
508 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
501 | after fork, and how you do this is entirely your own problem. |
509 | after fork, and how you do this is entirely your own problem. |
|
|
510 | |
|
|
511 | =item int ev_is_default_loop (loop) |
|
|
512 | |
|
|
513 | Returns true when the given loop actually is the default loop, false otherwise. |
502 | |
514 | |
503 | =item unsigned int ev_loop_count (loop) |
515 | =item unsigned int ev_loop_count (loop) |
504 | |
516 | |
505 | Returns the count of loop iterations for the loop, which is identical to |
517 | Returns the count of loop iterations for the loop, which is identical to |
506 | the number of times libev did poll for new events. It starts at C<0> and |
518 | the number of times libev did poll for new events. It starts at C<0> and |
… | |
… | |
605 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
617 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
606 | example, libev itself uses this for its internal signal pipe: It is not |
618 | example, libev itself uses this for its internal signal pipe: It is not |
607 | visible to the libev user and should not keep C<ev_loop> from exiting if |
619 | visible to the libev user and should not keep C<ev_loop> from exiting if |
608 | no event watchers registered by it are active. It is also an excellent |
620 | no event watchers registered by it are active. It is also an excellent |
609 | way to do this for generic recurring timers or from within third-party |
621 | way to do this for generic recurring timers or from within third-party |
610 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
622 | libraries. Just remember to I<unref after start> and I<ref before stop> |
|
|
623 | (but only if the watcher wasn't active before, or was active before, |
|
|
624 | respectively). |
611 | |
625 | |
612 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
626 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
613 | running when nothing else is active. |
627 | running when nothing else is active. |
614 | |
628 | |
615 | struct ev_signal exitsig; |
629 | struct ev_signal exitsig; |
… | |
… | |
763 | |
777 | |
764 | =item C<EV_FORK> |
778 | =item C<EV_FORK> |
765 | |
779 | |
766 | The event loop has been resumed in the child process after fork (see |
780 | The event loop has been resumed in the child process after fork (see |
767 | C<ev_fork>). |
781 | C<ev_fork>). |
|
|
782 | |
|
|
783 | =item C<EV_ASYNC> |
|
|
784 | |
|
|
785 | The given async watcher has been asynchronously notified (see C<ev_async>). |
768 | |
786 | |
769 | =item C<EV_ERROR> |
787 | =item C<EV_ERROR> |
770 | |
788 | |
771 | An unspecified error has occured, the watcher has been stopped. This might |
789 | An unspecified error has occured, the watcher has been stopped. This might |
772 | happen because the watcher could not be properly started because libev |
790 | happen because the watcher could not be properly started because libev |
… | |
… | |
1138 | configure a timer to trigger every 10 seconds, then it will trigger at |
1156 | configure a timer to trigger every 10 seconds, then it will trigger at |
1139 | exactly 10 second intervals. If, however, your program cannot keep up with |
1157 | exactly 10 second intervals. If, however, your program cannot keep up with |
1140 | the timer (because it takes longer than those 10 seconds to do stuff) the |
1158 | the timer (because it takes longer than those 10 seconds to do stuff) the |
1141 | timer will not fire more than once per event loop iteration. |
1159 | timer will not fire more than once per event loop iteration. |
1142 | |
1160 | |
1143 | =item ev_timer_again (loop) |
1161 | =item ev_timer_again (loop, ev_timer *) |
1144 | |
1162 | |
1145 | This will act as if the timer timed out and restart it again if it is |
1163 | This will act as if the timer timed out and restart it again if it is |
1146 | repeating. The exact semantics are: |
1164 | repeating. The exact semantics are: |
1147 | |
1165 | |
1148 | If the timer is pending, its pending status is cleared. |
1166 | If the timer is pending, its pending status is cleared. |
… | |
… | |
1257 | In this configuration the watcher triggers an event at the wallclock time |
1275 | In this configuration the watcher triggers an event at the wallclock time |
1258 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1276 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1259 | that is, if it is to be run at January 1st 2011 then it will run when the |
1277 | that is, if it is to be run at January 1st 2011 then it will run when the |
1260 | system time reaches or surpasses this time. |
1278 | system time reaches or surpasses this time. |
1261 | |
1279 | |
1262 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1280 | =item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1263 | |
1281 | |
1264 | In this mode the watcher will always be scheduled to time out at the next |
1282 | In this mode the watcher will always be scheduled to time out at the next |
1265 | C<at + N * interval> time (for some integer N, which can also be negative) |
1283 | C<at + N * interval> time (for some integer N, which can also be negative) |
1266 | and then repeat, regardless of any time jumps. |
1284 | and then repeat, regardless of any time jumps. |
1267 | |
1285 | |
… | |
… | |
1418 | |
1436 | |
1419 | The signal the watcher watches out for. |
1437 | The signal the watcher watches out for. |
1420 | |
1438 | |
1421 | =back |
1439 | =back |
1422 | |
1440 | |
|
|
1441 | =head3 Examples |
|
|
1442 | |
|
|
1443 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
|
|
1444 | |
|
|
1445 | static void |
|
|
1446 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
1447 | { |
|
|
1448 | ev_unloop (loop, EVUNLOOP_ALL); |
|
|
1449 | } |
|
|
1450 | |
|
|
1451 | struct ev_signal signal_watcher; |
|
|
1452 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
1453 | ev_signal_start (loop, &sigint_cb); |
|
|
1454 | |
1423 | |
1455 | |
1424 | =head2 C<ev_child> - watch out for process status changes |
1456 | =head2 C<ev_child> - watch out for process status changes |
1425 | |
1457 | |
1426 | Child watchers trigger when your process receives a SIGCHLD in response to |
1458 | Child watchers trigger when your process receives a SIGCHLD in response to |
1427 | some child status changes (most typically when a child of yours dies). |
1459 | some child status changes (most typically when a child of yours dies). It |
|
|
1460 | is permissible to install a child watcher I<after> the child has been |
|
|
1461 | forked (which implies it might have already exited), as long as the event |
|
|
1462 | loop isn't entered (or is continued from a watcher). |
|
|
1463 | |
|
|
1464 | Only the default event loop is capable of handling signals, and therefore |
|
|
1465 | you can only rgeister child watchers in the default event loop. |
|
|
1466 | |
|
|
1467 | =head3 Process Interaction |
|
|
1468 | |
|
|
1469 | Libev grabs C<SIGCHLD> as soon as the default event loop is |
|
|
1470 | initialised. This is necessary to guarantee proper behaviour even if |
|
|
1471 | the first child watcher is started after the child exits. The occurance |
|
|
1472 | of C<SIGCHLD> is recorded asynchronously, but child reaping is done |
|
|
1473 | synchronously as part of the event loop processing. Libev always reaps all |
|
|
1474 | children, even ones not watched. |
|
|
1475 | |
|
|
1476 | =head3 Overriding the Built-In Processing |
|
|
1477 | |
|
|
1478 | Libev offers no special support for overriding the built-in child |
|
|
1479 | processing, but if your application collides with libev's default child |
|
|
1480 | handler, you can override it easily by installing your own handler for |
|
|
1481 | C<SIGCHLD> after initialising the default loop, and making sure the |
|
|
1482 | default loop never gets destroyed. You are encouraged, however, to use an |
|
|
1483 | event-based approach to child reaping and thus use libev's support for |
|
|
1484 | that, so other libev users can use C<ev_child> watchers freely. |
1428 | |
1485 | |
1429 | =head3 Watcher-Specific Functions and Data Members |
1486 | =head3 Watcher-Specific Functions and Data Members |
1430 | |
1487 | |
1431 | =over 4 |
1488 | =over 4 |
1432 | |
1489 | |
1433 | =item ev_child_init (ev_child *, callback, int pid) |
1490 | =item ev_child_init (ev_child *, callback, int pid, int trace) |
1434 | |
1491 | |
1435 | =item ev_child_set (ev_child *, int pid) |
1492 | =item ev_child_set (ev_child *, int pid, int trace) |
1436 | |
1493 | |
1437 | Configures the watcher to wait for status changes of process C<pid> (or |
1494 | Configures the watcher to wait for status changes of process C<pid> (or |
1438 | I<any> process if C<pid> is specified as C<0>). The callback can look |
1495 | I<any> process if C<pid> is specified as C<0>). The callback can look |
1439 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1496 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1440 | the status word (use the macros from C<sys/wait.h> and see your systems |
1497 | the status word (use the macros from C<sys/wait.h> and see your systems |
1441 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1498 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1442 | process causing the status change. |
1499 | process causing the status change. C<trace> must be either C<0> (only |
|
|
1500 | activate the watcher when the process terminates) or C<1> (additionally |
|
|
1501 | activate the watcher when the process is stopped or continued). |
1443 | |
1502 | |
1444 | =item int pid [read-only] |
1503 | =item int pid [read-only] |
1445 | |
1504 | |
1446 | The process id this watcher watches out for, or C<0>, meaning any process id. |
1505 | The process id this watcher watches out for, or C<0>, meaning any process id. |
1447 | |
1506 | |
… | |
… | |
1456 | |
1515 | |
1457 | =back |
1516 | =back |
1458 | |
1517 | |
1459 | =head3 Examples |
1518 | =head3 Examples |
1460 | |
1519 | |
1461 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1520 | Example: C<fork()> a new process and install a child handler to wait for |
|
|
1521 | its completion. |
|
|
1522 | |
|
|
1523 | ev_child cw; |
1462 | |
1524 | |
1463 | static void |
1525 | static void |
1464 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1526 | child_cb (EV_P_ struct ev_child *w, int revents) |
1465 | { |
1527 | { |
1466 | ev_unloop (loop, EVUNLOOP_ALL); |
1528 | ev_child_stop (EV_A_ w); |
|
|
1529 | printf ("process %d exited with status %x\n", w->rpid, w->rstatus); |
1467 | } |
1530 | } |
1468 | |
1531 | |
1469 | struct ev_signal signal_watcher; |
1532 | pid_t pid = fork (); |
1470 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1533 | |
1471 | ev_signal_start (loop, &sigint_cb); |
1534 | if (pid < 0) |
|
|
1535 | // error |
|
|
1536 | else if (pid == 0) |
|
|
1537 | { |
|
|
1538 | // the forked child executes here |
|
|
1539 | exit (1); |
|
|
1540 | } |
|
|
1541 | else |
|
|
1542 | { |
|
|
1543 | ev_child_init (&cw, child_cb, pid, 0); |
|
|
1544 | ev_child_start (EV_DEFAULT_ &cw); |
|
|
1545 | } |
1472 | |
1546 | |
1473 | |
1547 | |
1474 | =head2 C<ev_stat> - did the file attributes just change? |
1548 | =head2 C<ev_stat> - did the file attributes just change? |
1475 | |
1549 | |
1476 | This watches a filesystem path for attribute changes. That is, it calls |
1550 | This watches a filesystem path for attribute changes. That is, it calls |
… | |
… | |
1556 | |
1630 | |
1557 | The callback will be receive C<EV_STAT> when a change was detected, |
1631 | The callback will be receive C<EV_STAT> when a change was detected, |
1558 | relative to the attributes at the time the watcher was started (or the |
1632 | relative to the attributes at the time the watcher was started (or the |
1559 | last change was detected). |
1633 | last change was detected). |
1560 | |
1634 | |
1561 | =item ev_stat_stat (ev_stat *) |
1635 | =item ev_stat_stat (loop, ev_stat *) |
1562 | |
1636 | |
1563 | Updates the stat buffer immediately with new values. If you change the |
1637 | Updates the stat buffer immediately with new values. If you change the |
1564 | watched path in your callback, you could call this fucntion to avoid |
1638 | watched path in your callback, you could call this fucntion to avoid |
1565 | detecting this change (while introducing a race condition). Can also be |
1639 | detecting this change (while introducing a race condition). Can also be |
1566 | useful simply to find out the new values. |
1640 | useful simply to find out the new values. |
… | |
… | |
1683 | static void |
1757 | static void |
1684 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1758 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1685 | { |
1759 | { |
1686 | free (w); |
1760 | free (w); |
1687 | // now do something you wanted to do when the program has |
1761 | // now do something you wanted to do when the program has |
1688 | // no longer asnything immediate to do. |
1762 | // no longer anything immediate to do. |
1689 | } |
1763 | } |
1690 | |
1764 | |
1691 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1765 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1692 | ev_idle_init (idle_watcher, idle_cb); |
1766 | ev_idle_init (idle_watcher, idle_cb); |
1693 | ev_idle_start (loop, idle_cb); |
1767 | ev_idle_start (loop, idle_cb); |
… | |
… | |
2034 | believe me. |
2108 | believe me. |
2035 | |
2109 | |
2036 | =back |
2110 | =back |
2037 | |
2111 | |
2038 | |
2112 | |
|
|
2113 | =head2 C<ev_async> - how to wake up another event loop |
|
|
2114 | |
|
|
2115 | In general, you cannot use an C<ev_loop> from multiple threads or other |
|
|
2116 | asynchronous sources such as signal handlers (as opposed to multiple event |
|
|
2117 | loops - those are of course safe to use in different threads). |
|
|
2118 | |
|
|
2119 | Sometimes, however, you need to wake up another event loop you do not |
|
|
2120 | control, for example because it belongs to another thread. This is what |
|
|
2121 | C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you |
|
|
2122 | can signal it by calling C<ev_async_send>, which is thread- and signal |
|
|
2123 | safe. |
|
|
2124 | |
|
|
2125 | This functionality is very similar to C<ev_signal> watchers, as signals, |
|
|
2126 | too, are asynchronous in nature, and signals, too, will be compressed |
|
|
2127 | (i.e. the number of callback invocations may be less than the number of |
|
|
2128 | C<ev_async_sent> calls). |
|
|
2129 | |
|
|
2130 | Unlike C<ev_signal> watchers, C<ev_async> works with any event loop, not |
|
|
2131 | just the default loop. |
|
|
2132 | |
|
|
2133 | =head3 Queueing |
|
|
2134 | |
|
|
2135 | C<ev_async> does not support queueing of data in any way. The reason |
|
|
2136 | is that the author does not know of a simple (or any) algorithm for a |
|
|
2137 | multiple-writer-single-reader queue that works in all cases and doesn't |
|
|
2138 | need elaborate support such as pthreads. |
|
|
2139 | |
|
|
2140 | That means that if you want to queue data, you have to provide your own |
|
|
2141 | queue. But at least I can tell you would implement locking around your |
|
|
2142 | queue: |
|
|
2143 | |
|
|
2144 | =over 4 |
|
|
2145 | |
|
|
2146 | =item queueing from a signal handler context |
|
|
2147 | |
|
|
2148 | To implement race-free queueing, you simply add to the queue in the signal |
|
|
2149 | handler but you block the signal handler in the watcher callback. Here is an example that does that for |
|
|
2150 | some fictitiuous SIGUSR1 handler: |
|
|
2151 | |
|
|
2152 | static ev_async mysig; |
|
|
2153 | |
|
|
2154 | static void |
|
|
2155 | sigusr1_handler (void) |
|
|
2156 | { |
|
|
2157 | sometype data; |
|
|
2158 | |
|
|
2159 | // no locking etc. |
|
|
2160 | queue_put (data); |
|
|
2161 | ev_async_send (EV_DEFAULT_ &mysig); |
|
|
2162 | } |
|
|
2163 | |
|
|
2164 | static void |
|
|
2165 | mysig_cb (EV_P_ ev_async *w, int revents) |
|
|
2166 | { |
|
|
2167 | sometype data; |
|
|
2168 | sigset_t block, prev; |
|
|
2169 | |
|
|
2170 | sigemptyset (&block); |
|
|
2171 | sigaddset (&block, SIGUSR1); |
|
|
2172 | sigprocmask (SIG_BLOCK, &block, &prev); |
|
|
2173 | |
|
|
2174 | while (queue_get (&data)) |
|
|
2175 | process (data); |
|
|
2176 | |
|
|
2177 | if (sigismember (&prev, SIGUSR1) |
|
|
2178 | sigprocmask (SIG_UNBLOCK, &block, 0); |
|
|
2179 | } |
|
|
2180 | |
|
|
2181 | (Note: pthreads in theory requires you to use C<pthread_setmask> |
|
|
2182 | instead of C<sigprocmask> when you use threads, but libev doesn't do it |
|
|
2183 | either...). |
|
|
2184 | |
|
|
2185 | =item queueing from a thread context |
|
|
2186 | |
|
|
2187 | The strategy for threads is different, as you cannot (easily) block |
|
|
2188 | threads but you can easily preempt them, so to queue safely you need to |
|
|
2189 | employ a traditional mutex lock, such as in this pthread example: |
|
|
2190 | |
|
|
2191 | static ev_async mysig; |
|
|
2192 | static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER; |
|
|
2193 | |
|
|
2194 | static void |
|
|
2195 | otherthread (void) |
|
|
2196 | { |
|
|
2197 | // only need to lock the actual queueing operation |
|
|
2198 | pthread_mutex_lock (&mymutex); |
|
|
2199 | queue_put (data); |
|
|
2200 | pthread_mutex_unlock (&mymutex); |
|
|
2201 | |
|
|
2202 | ev_async_send (EV_DEFAULT_ &mysig); |
|
|
2203 | } |
|
|
2204 | |
|
|
2205 | static void |
|
|
2206 | mysig_cb (EV_P_ ev_async *w, int revents) |
|
|
2207 | { |
|
|
2208 | pthread_mutex_lock (&mymutex); |
|
|
2209 | |
|
|
2210 | while (queue_get (&data)) |
|
|
2211 | process (data); |
|
|
2212 | |
|
|
2213 | pthread_mutex_unlock (&mymutex); |
|
|
2214 | } |
|
|
2215 | |
|
|
2216 | =back |
|
|
2217 | |
|
|
2218 | |
|
|
2219 | =head3 Watcher-Specific Functions and Data Members |
|
|
2220 | |
|
|
2221 | =over 4 |
|
|
2222 | |
|
|
2223 | =item ev_async_init (ev_async *, callback) |
|
|
2224 | |
|
|
2225 | Initialises and configures the async watcher - it has no parameters of any |
|
|
2226 | kind. There is a C<ev_asynd_set> macro, but using it is utterly pointless, |
|
|
2227 | believe me. |
|
|
2228 | |
|
|
2229 | =item ev_async_send (loop, ev_async *) |
|
|
2230 | |
|
|
2231 | Sends/signals/activates the given C<ev_async> watcher, that is, feeds |
|
|
2232 | an C<EV_ASYNC> event on the watcher into the event loop. Unlike |
|
|
2233 | C<ev_feed_event>, this call is safe to do in other threads, signal or |
|
|
2234 | similar contexts (see the dicusssion of C<EV_ATOMIC_T> in the embedding |
|
|
2235 | section below on what exactly this means). |
|
|
2236 | |
|
|
2237 | This call incurs the overhead of a syscall only once per loop iteration, |
|
|
2238 | so while the overhead might be noticable, it doesn't apply to repeated |
|
|
2239 | calls to C<ev_async_send>. |
|
|
2240 | |
|
|
2241 | =back |
|
|
2242 | |
|
|
2243 | |
2039 | =head1 OTHER FUNCTIONS |
2244 | =head1 OTHER FUNCTIONS |
2040 | |
2245 | |
2041 | There are some other functions of possible interest. Described. Here. Now. |
2246 | There are some other functions of possible interest. Described. Here. Now. |
2042 | |
2247 | |
2043 | =over 4 |
2248 | =over 4 |
… | |
… | |
2270 | Example: Define a class with an IO and idle watcher, start one of them in |
2475 | Example: Define a class with an IO and idle watcher, start one of them in |
2271 | the constructor. |
2476 | the constructor. |
2272 | |
2477 | |
2273 | class myclass |
2478 | class myclass |
2274 | { |
2479 | { |
2275 | ev_io io; void io_cb (ev::io &w, int revents); |
2480 | ev::io io; void io_cb (ev::io &w, int revents); |
2276 | ev_idle idle void idle_cb (ev::idle &w, int revents); |
2481 | ev:idle idle void idle_cb (ev::idle &w, int revents); |
2277 | |
2482 | |
2278 | myclass (); |
2483 | myclass (int fd) |
2279 | } |
|
|
2280 | |
|
|
2281 | myclass::myclass (int fd) |
|
|
2282 | { |
2484 | { |
2283 | io .set <myclass, &myclass::io_cb > (this); |
2485 | io .set <myclass, &myclass::io_cb > (this); |
2284 | idle.set <myclass, &myclass::idle_cb> (this); |
2486 | idle.set <myclass, &myclass::idle_cb> (this); |
2285 | |
2487 | |
2286 | io.start (fd, ev::READ); |
2488 | io.start (fd, ev::READ); |
|
|
2489 | } |
2287 | } |
2490 | }; |
2288 | |
2491 | |
2289 | |
2492 | |
2290 | =head1 MACRO MAGIC |
2493 | =head1 MACRO MAGIC |
2291 | |
2494 | |
2292 | Libev can be compiled with a variety of options, the most fundamantal |
2495 | Libev can be compiled with a variety of options, the most fundamantal |
… | |
… | |
2548 | |
2751 | |
2549 | If defined to be C<1>, libev will compile in support for the Linux inotify |
2752 | If defined to be C<1>, libev will compile in support for the Linux inotify |
2550 | interface to speed up C<ev_stat> watchers. Its actual availability will |
2753 | interface to speed up C<ev_stat> watchers. Its actual availability will |
2551 | be detected at runtime. |
2754 | be detected at runtime. |
2552 | |
2755 | |
|
|
2756 | =item EV_ATOMIC_T |
|
|
2757 | |
|
|
2758 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
|
|
2759 | access is atomic with respect to other threads or signal contexts. No such |
|
|
2760 | type is easily found in the C language, so you can provide your own type |
|
|
2761 | that you know is safe for your purposes. It is used both for signal handler "locking" |
|
|
2762 | as well as for signal and thread safety in C<ev_async> watchers. |
|
|
2763 | |
|
|
2764 | In the absense of this define, libev will use C<sig_atomic_t volatile> |
|
|
2765 | (from F<signal.h>), which is usually good enough on most platforms. |
|
|
2766 | |
2553 | =item EV_H |
2767 | =item EV_H |
2554 | |
2768 | |
2555 | The name of the F<ev.h> header file used to include it. The default if |
2769 | The name of the F<ev.h> header file used to include it. The default if |
2556 | undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to |
2770 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
2557 | virtually rename the F<ev.h> header file in case of conflicts. |
2771 | used to virtually rename the F<ev.h> header file in case of conflicts. |
2558 | |
2772 | |
2559 | =item EV_CONFIG_H |
2773 | =item EV_CONFIG_H |
2560 | |
2774 | |
2561 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2775 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2562 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2776 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2563 | C<EV_H>, above. |
2777 | C<EV_H>, above. |
2564 | |
2778 | |
2565 | =item EV_EVENT_H |
2779 | =item EV_EVENT_H |
2566 | |
2780 | |
2567 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2781 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2568 | of how the F<event.h> header can be found, the dfeault is C<"event.h">. |
2782 | of how the F<event.h> header can be found, the default is C<"event.h">. |
2569 | |
2783 | |
2570 | =item EV_PROTOTYPES |
2784 | =item EV_PROTOTYPES |
2571 | |
2785 | |
2572 | If defined to be C<0>, then F<ev.h> will not define any function |
2786 | If defined to be C<0>, then F<ev.h> will not define any function |
2573 | prototypes, but still define all the structs and other symbols. This is |
2787 | prototypes, but still define all the structs and other symbols. This is |
… | |
… | |
2622 | defined to be C<0>, then they are not. |
2836 | defined to be C<0>, then they are not. |
2623 | |
2837 | |
2624 | =item EV_FORK_ENABLE |
2838 | =item EV_FORK_ENABLE |
2625 | |
2839 | |
2626 | If undefined or defined to be C<1>, then fork watchers are supported. If |
2840 | If undefined or defined to be C<1>, then fork watchers are supported. If |
|
|
2841 | defined to be C<0>, then they are not. |
|
|
2842 | |
|
|
2843 | =item EV_ASYNC_ENABLE |
|
|
2844 | |
|
|
2845 | If undefined or defined to be C<1>, then async watchers are supported. If |
2627 | defined to be C<0>, then they are not. |
2846 | defined to be C<0>, then they are not. |
2628 | |
2847 | |
2629 | =item EV_MINIMAL |
2848 | =item EV_MINIMAL |
2630 | |
2849 | |
2631 | If you need to shave off some kilobytes of code at the expense of some |
2850 | If you need to shave off some kilobytes of code at the expense of some |
… | |
… | |
2752 | =item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers) |
2971 | =item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers) |
2753 | |
2972 | |
2754 | That means that changing a timer costs less than removing/adding them |
2973 | That means that changing a timer costs less than removing/adding them |
2755 | as only the relative motion in the event queue has to be paid for. |
2974 | as only the relative motion in the event queue has to be paid for. |
2756 | |
2975 | |
2757 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2976 | =item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1) |
2758 | |
2977 | |
2759 | These just add the watcher into an array or at the head of a list. |
2978 | These just add the watcher into an array or at the head of a list. |
2760 | |
2979 | |
2761 | =item Stopping check/prepare/idle watchers: O(1) |
2980 | =item Stopping check/prepare/idle/fork/async watchers: O(1) |
2762 | |
2981 | |
2763 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2982 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2764 | |
2983 | |
2765 | These watchers are stored in lists then need to be walked to find the |
2984 | These watchers are stored in lists then need to be walked to find the |
2766 | correct watcher to remove. The lists are usually short (you don't usually |
2985 | correct watcher to remove. The lists are usually short (you don't usually |
… | |
… | |
2782 | =item Priority handling: O(number_of_priorities) |
3001 | =item Priority handling: O(number_of_priorities) |
2783 | |
3002 | |
2784 | Priorities are implemented by allocating some space for each |
3003 | Priorities are implemented by allocating some space for each |
2785 | priority. When doing priority-based operations, libev usually has to |
3004 | priority. When doing priority-based operations, libev usually has to |
2786 | linearly search all the priorities, but starting/stopping and activating |
3005 | linearly search all the priorities, but starting/stopping and activating |
2787 | watchers becomes O(1) w.r.t. prioritiy handling. |
3006 | watchers becomes O(1) w.r.t. priority handling. |
|
|
3007 | |
|
|
3008 | =item Sending an ev_async: O(1) |
|
|
3009 | |
|
|
3010 | =item Processing ev_async_send: O(number_of_async_watchers) |
|
|
3011 | |
|
|
3012 | =item Processing signals: O(max_signal_number) |
|
|
3013 | |
|
|
3014 | Sending involves a syscall I<iff> there were no other C<ev_async_send> |
|
|
3015 | calls in the current loop iteration. Checking for async and signal events |
|
|
3016 | involves iterating over all running async watchers or all signal numbers. |
2788 | |
3017 | |
2789 | =back |
3018 | =back |
2790 | |
3019 | |
2791 | |
3020 | |
2792 | =head1 Win32 platform limitations and workarounds |
3021 | =head1 Win32 platform limitations and workarounds |