… | |
… | |
265 | or setgid) then libev will I<not> look at the environment variable |
265 | or setgid) then libev will I<not> look at the environment variable |
266 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
266 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
267 | override the flags completely if it is found in the environment. This is |
267 | override the flags completely if it is found in the environment. This is |
268 | useful to try out specific backends to test their performance, or to work |
268 | useful to try out specific backends to test their performance, or to work |
269 | around bugs. |
269 | around bugs. |
|
|
270 | |
|
|
271 | =item C<EVFLAG_FORKCHECK> |
|
|
272 | |
|
|
273 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
|
274 | a fork, you can also make libev check for a fork in each iteration by |
|
|
275 | enabling this flag. |
|
|
276 | |
|
|
277 | This works by calling C<getpid ()> on every iteration of the loop, |
|
|
278 | and thus this might slow down your event loop if you do a lot of loop |
|
|
279 | iterations and little real work, but is usually not noticable (on my |
|
|
280 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
|
281 | without a syscall and thus I<very> fast, but my Linux system also has |
|
|
282 | C<pthread_atfork> which is even faster). |
|
|
283 | |
|
|
284 | The big advantage of this flag is that you can forget about fork (and |
|
|
285 | forget about forgetting to tell libev about forking) when you use this |
|
|
286 | flag. |
|
|
287 | |
|
|
288 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
|
289 | environment variable. |
270 | |
290 | |
271 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
291 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
272 | |
292 | |
273 | This is your standard select(2) backend. Not I<completely> standard, as |
293 | This is your standard select(2) backend. Not I<completely> standard, as |
274 | libev tries to roll its own fd_set with no limits on the number of fds, |
294 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
916 | =item ev_timer_again (loop) |
936 | =item ev_timer_again (loop) |
917 | |
937 | |
918 | This will act as if the timer timed out and restart it again if it is |
938 | This will act as if the timer timed out and restart it again if it is |
919 | repeating. The exact semantics are: |
939 | repeating. The exact semantics are: |
920 | |
940 | |
|
|
941 | If the timer is pending, its pending status is cleared. |
|
|
942 | |
921 | If the timer is started but nonrepeating, stop it. |
943 | If the timer is started but nonrepeating, stop it (as if it timed out). |
922 | |
944 | |
923 | If the timer is repeating, either start it if necessary (with the repeat |
945 | If the timer is repeating, either start it if necessary (with the |
924 | value), or reset the running timer to the repeat value. |
946 | C<repeat> value), or reset the running timer to the C<repeat> value. |
925 | |
947 | |
926 | This sounds a bit complicated, but here is a useful and typical |
948 | This sounds a bit complicated, but here is a useful and typical |
927 | example: Imagine you have a tcp connection and you want a so-called |
949 | example: Imagine you have a tcp connection and you want a so-called idle |
928 | idle timeout, that is, you want to be called when there have been, |
950 | timeout, that is, you want to be called when there have been, say, 60 |
929 | say, 60 seconds of inactivity on the socket. The easiest way to do |
951 | seconds of inactivity on the socket. The easiest way to do this is to |
930 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
952 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
931 | C<ev_timer_again> each time you successfully read or write some data. If |
953 | C<ev_timer_again> each time you successfully read or write some data. If |
932 | you go into an idle state where you do not expect data to travel on the |
954 | you go into an idle state where you do not expect data to travel on the |
933 | socket, you can stop the timer, and again will automatically restart it if |
955 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
934 | need be. |
956 | automatically restart it if need be. |
935 | |
957 | |
936 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
958 | That means you can ignore the C<after> value and C<ev_timer_start> |
937 | and only ever use the C<repeat> value: |
959 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
938 | |
960 | |
939 | ev_timer_init (timer, callback, 0., 5.); |
961 | ev_timer_init (timer, callback, 0., 5.); |
940 | ev_timer_again (loop, timer); |
962 | ev_timer_again (loop, timer); |
941 | ... |
963 | ... |
942 | timer->again = 17.; |
964 | timer->again = 17.; |
943 | ev_timer_again (loop, timer); |
965 | ev_timer_again (loop, timer); |
944 | ... |
966 | ... |
945 | timer->again = 10.; |
967 | timer->again = 10.; |
946 | ev_timer_again (loop, timer); |
968 | ev_timer_again (loop, timer); |
947 | |
969 | |
948 | This is more efficient then stopping/starting the timer eahc time you want |
970 | This is more slightly efficient then stopping/starting the timer each time |
949 | to modify its timeout value. |
971 | you want to modify its timeout value. |
950 | |
972 | |
951 | =item ev_tstamp repeat [read-write] |
973 | =item ev_tstamp repeat [read-write] |
952 | |
974 | |
953 | The current C<repeat> value. Will be used each time the watcher times out |
975 | The current C<repeat> value. Will be used each time the watcher times out |
954 | or C<ev_timer_again> is called and determines the next timeout (if any), |
976 | or C<ev_timer_again> is called and determines the next timeout (if any), |
… | |
… | |
1222 | The path does not need to exist: changing from "path exists" to "path does |
1244 | The path does not need to exist: changing from "path exists" to "path does |
1223 | not exist" is a status change like any other. The condition "path does |
1245 | not exist" is a status change like any other. The condition "path does |
1224 | not exist" is signified by the C<st_nlink> field being zero (which is |
1246 | not exist" is signified by the C<st_nlink> field being zero (which is |
1225 | otherwise always forced to be at least one) and all the other fields of |
1247 | otherwise always forced to be at least one) and all the other fields of |
1226 | the stat buffer having unspecified contents. |
1248 | the stat buffer having unspecified contents. |
|
|
1249 | |
|
|
1250 | The path I<should> be absolute and I<must not> end in a slash. If it is |
|
|
1251 | relative and your working directory changes, the behaviour is undefined. |
1227 | |
1252 | |
1228 | Since there is no standard to do this, the portable implementation simply |
1253 | Since there is no standard to do this, the portable implementation simply |
1229 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
1254 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
1230 | can specify a recommended polling interval for this case. If you specify |
1255 | can specify a recommended polling interval for this case. If you specify |
1231 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1256 | a polling interval of C<0> (highly recommended!) then a I<suitable, |