--- IO-AIO/README 2007/08/05 16:45:54 1.24 +++ IO-AIO/README 2008/04/16 16:45:30 1.29 @@ -26,10 +26,13 @@ my $grp = aio_group sub { print "all stats done\n" }; add $grp aio_stat "..." for ...; - # AnyEvent integration + # AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...) open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); + # 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, poll => 'r', @@ -260,13 +263,18 @@ 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) @@ -275,9 +283,9 @@ callback without the actual number of bytes read (or -1 on error, just like the syscall). - If $offset is undefined, then the current file offset will be used - (and updated), otherwise the file offset will not be changed by - these calls. + If $offset is undefined, then the current file descriptor offset + will be used (and updated), otherwise the file descriptor offset + will not be changed by these calls. If $length is undefined in "aio_write", use the remaining length of $data. @@ -523,6 +531,9 @@ 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 +545,16 @@ 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 +645,16 @@ 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 +681,7 @@ $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. @@ -853,7 +877,7 @@ it blocks, and a bad way to reduce concurrency because it is inexact: Better use an "aio_group" together with a feed callback. - Sets the maximum number of outstanding requests to $nreqs. If you to + Sets the maximum number of outstanding requests to $nreqs. If you do queue up more than this number of requests, the next call to the "poll_cb" (and "poll_some" and other functions calling "poll_cb") function will block until the limit is no longer exceeded. @@ -909,7 +933,7 @@ scalars and other data passed into aio requests will also be locked and will consume memory till the request has entered the done state. - This is now awfully much, so queuing lots of requests is not usually a + This is not awfully much, so queuing lots of requests is not usually a problem. Per-thread usage: