ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev.pod
(Generate patch)

Comparing libev/ev.pod (file contents):
Revision 1.146 by root, Fri Apr 11 00:31:19 2008 UTC vs.
Revision 1.149 by root, Fri May 2 08:36:20 2008 UTC

… …
1373Simply stops and restarts the periodic watcher again. This is only useful 1373Simply stops and restarts the periodic watcher again. This is only useful
1374when you changed some parameters or the reschedule callback would return 1374when you changed some parameters or the reschedule callback would return
1375a different time than the last time it was called (e.g. in a crond like 1375a different time than the last time it was called (e.g. in a crond like
1376program when the crontabs have changed). 1376program when the crontabs have changed).
1377 1377
1378=item ev_tstamp ev_periodic_at (ev_periodic *)
1379
1380When active, returns the absolute time that the watcher is supposed to
1381trigger next.
1382
1378=item ev_tstamp offset [read-write] 1383=item ev_tstamp offset [read-write]
1379 1384
1380When repeating, this contains the offset value, otherwise this is the 1385When repeating, this contains the offset value, otherwise this is the
1381absolute point in time (the C<at> value passed to C<ev_periodic_set>). 1386absolute point in time (the C<at> value passed to C<ev_periodic_set>).
1382 1387
… …
1392=item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] 1397=item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]
1393 1398
1394The current reschedule callback, or C<0>, if this functionality is 1399The current reschedule callback, or C<0>, if this functionality is
1395switched off. Can be changed any time, but changes only take effect when 1400switched off. Can be changed any time, but changes only take effect when
1396the periodic timer fires or C<ev_periodic_again> is being called. 1401the periodic timer fires or C<ev_periodic_again> is being called.
1397
1398=item ev_tstamp at [read-only]
1399
1400When active, contains the absolute time that the watcher is supposed to
1401trigger next.
1402 1402
1403=back 1403=back
1404 1404
1405=head3 Examples 1405=head3 Examples
1406 1406
… …
1634When C<inotify (7)> support has been compiled into libev (generally only 1634When C<inotify (7)> support has been compiled into libev (generally only
1635available on Linux) and present at runtime, it will be used to speed up 1635available on Linux) and present at runtime, it will be used to speed up
1636change detection where possible. The inotify descriptor will be created lazily 1636change detection where possible. The inotify descriptor will be created lazily
1637when the first C<ev_stat> watcher is being started. 1637when the first C<ev_stat> watcher is being started.
1638 1638
1639Inotify presense does not change the semantics of C<ev_stat> watchers 1639Inotify presence does not change the semantics of C<ev_stat> watchers
1640except that changes might be detected earlier, and in some cases, to avoid 1640except that changes might be detected earlier, and in some cases, to avoid
1641making regular C<stat> calls. Even in the presense of inotify support 1641making regular C<stat> calls. Even in the presence of inotify support
1642there are many cases where libev has to resort to regular C<stat> polling. 1642there are many cases where libev has to resort to regular C<stat> polling.
1643 1643
1644(There is no support for kqueue, as apparently it cannot be used to 1644(There is no support for kqueue, as apparently it cannot be used to
1645implement this functionality, due to the requirement of having a file 1645implement this functionality, due to the requirement of having a file
1646descriptor open on the object at all times). 1646descriptor open on the object at all times).
… …
3260calling select (O(n²)) will likely make this unworkable. 3260calling select (O(n²)) will likely make this unworkable.
3261 3261
3262=back 3262=back
3263 3263
3264 3264
3265=head1 PORTABILITY REQUIREMENTS
3266
3267In addition to a working ISO-C implementation, libev relies on a few
3268additional extensions:
3269
3270=over 4
3271
3272=item C<sig_atomic_t volatile> must be thread-atomic as well
3273
3274The type C<sig_atomic_t volatile> (or whatever is defined as
3275C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different
3276threads. This is not part of the specification for C<sig_atomic_t>, but is
3277believed to be sufficiently portable.
3278
3279=item C<sigprocmask> must work in a threaded environment
3280
3281Libev uses C<sigprocmask> to temporarily block signals. This is not
3282allowed in a threaded program (C<pthread_sigmask> has to be used). Typical
3283pthread implementations will either allow C<sigprocmask> in the "main
3284thread" or will block signals process-wide, both behaviours would
3285be compatible with libev. Interaction between C<sigprocmask> and
3286C<pthread_sigmask> could complicate things, however.
3287
3288The most portable way to handle signals is to block signals in all threads
3289except the initial one, and run the default loop in the initial thread as
3290well.
3291
3292=back
3293
3294If you know of other additional requirements drop me a note.
3295
3296
3265=head1 AUTHOR 3297=head1 AUTHOR
3266 3298
3267Marc Lehmann <libev@schmorp.de>. 3299Marc Lehmann <libev@schmorp.de>.
3268 3300

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines