--- IO-AIO/README 2007/09/24 19:28:50 1.25 +++ IO-AIO/README 2008/05/29 03:35:03 1.31 @@ -26,9 +26,11 @@ my $grp = aio_group sub { print "all stats done\n" }; add $grp aio_stat "..." for ...; - # AnyEvent integration - open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; - my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); + # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) + use AnyEvent::AIO; + + # EV integration + my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; # Event integration Event->io (fd => IO::AIO::poll_fileno, @@ -260,13 +262,18 @@ aio_close $fh, $callback->($status) Asynchronously close a file and call the callback with the result - code. *WARNING:* although accepted, you should not pass in a perl - filehandle here, as perl will likely close the file descriptor - another time when the filehandle is destroyed. Normally, you can - safely call perls "close" or just let filehandles go out of scope. + code. + + Unfortunately, you can't do this to perl. Perl *insists* very + strongly on closing the file descriptor associated with the + filehandle itself. + + Therefore, "aio_close" will not close the filehandle - instead it + will use dup2 to overwrite the file descriptor with the write-end of + a pipe (the pipe fd will be created on demand and will be cached). - This is supposed to be a bug in the API, so that might change. It's - therefore best to avoid this function. + Or in other words: the file descriptor will be closed, but it will + not be free for reuse until the perl filehandle is closed. aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) @@ -523,6 +530,9 @@ uses "aio_scandir" to recurse into and rmdir directories, and unlink everything else. + aio_sync $callback->($status) + Asynchronously call sync and call the callback when finished. + aio_fsync $fh, $callback->($status) Asynchronously call fsync on the given filehandle and call the callback with the fsync result code. @@ -534,6 +544,16 @@ If this call isn't available because your OS lacks it or it couldn't be detected, it will be emulated by calling "fsync" instead. + aio_pathsync $path, $callback->($status) + This request tries to open, fsync and close the given path. This is + a composite request intended tosync directories after directory + operations (E.g. rename). This might not work on all operating + systems or have any specific effect, but usually it makes sure that + directory changes get written to disc. It works for anything that + can be opened for read-only, not just directories. + + Passes 0 when everything went ok, and -1 on error. + aio_group $callback->(...) This is a very special aio request: Instead of doing something, it is a container for other aio requests, which is useful if you want @@ -624,13 +644,16 @@ This makes it very easy to create composite requests (see the source of "aio_move" for an application) that work and feel like simple requests. - * The IO::AIO::GRP objects will be cleaned up during calls to - "IO::AIO::poll_cb", just like any other request. - * They can be canceled like any other request. Canceling will cancel not - only the request itself, but also all requests it contains. - * They can also can also be added to other IO::AIO::GRP objects. - * You must not add requests to a group from within the group callback - (or any later time). + * The IO::AIO::GRP objects will be cleaned up during calls to + "IO::AIO::poll_cb", just like any other request. + + * They can be canceled like any other request. Canceling will cancel + not only the request itself, but also all requests it contains. + + * They can also can also be added to other IO::AIO::GRP objects. + + * You must not add requests to a group from within the group callback + (or any later time). Their lifetime, simplified, looks like this: when they are empty, they will finish very quickly. If they contain only requests that are in the @@ -657,7 +680,7 @@ $grp->result (...) Set the result value(s) that will be passed to the group callback - when all subrequests have finished and set thre groups errno to the + when all subrequests have finished and set the groups errno to the current value of errno (just like calling "errno" without an error number). By default, no argument will be passed and errno is zero. @@ -726,13 +749,15 @@ IO::AIO::poll_cb Process some outstanding events on the result pipe. You have to call - this regularly. Returns the number of events processed. Returns - immediately when no events are outstanding. The amount of events - processed depends on the settings of "IO::AIO::max_poll_req" and + this regularly. Returns 0 if all events could be processed, or -1 if + it returned earlier for whatever reason. Returns immediately when no + events are outstanding. The amount of events processed depends on + the settings of "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". If not all requests were processed for whatever reason, the - filehandle will still be ready when "poll_cb" returns. + filehandle will still be ready when "poll_cb" returns, so normally + you don't have to do anything special to have it called later. Example: Install an Event watcher that automatically calls IO::AIO::poll_cb with high priority: @@ -848,7 +873,7 @@ creation is fast. If thread creation is very slow on your system you might want to use larger values. - $oldmaxreqs = IO::AIO::max_outstanding $maxreqs + IO::AIO::max_outstanding $maxreqs This is a very bad function to use in interactive programs because it blocks, and a bad way to reduce concurrency because it is inexact: Better use an "aio_group" together with a feed callback. @@ -862,7 +887,7 @@ the number of outstanding requests. You can still queue as many requests as you want. Therefore, - "max_oustsanding" is mainly useful in simple scripts (with low + "max_outstanding" is mainly useful in simple scripts (with low values) or as a stop gap to shield against fatal memory overflow (with large values). @@ -922,7 +947,8 @@ Known bugs will be fixed in the next release. SEE ALSO - Coro::AIO. + AnyEvent::AIO for easy integration into event loops, Coro::AIO for a + more natural syntax. AUTHOR Marc Lehmann