On Thu, May 20, 2010 at 05:54:05PM -0600, Lars Holowko
<[email protected]> wrote:
> my $fn = "tail -f /var/log/messages";
> open my $fh, '-|', $fn or croak "Can't open $fn: $::OS_ERROR";
starting an external process per file is not quite low-overhead, but
certainly easy to implement...
> my $watcher = EV::io $fh, EV::READ, sub {
>
> my ($watcher, $revents) = @_;
>
> warn "yeah, /var/log/messages should now be readable without
> blocking!\n";
No, not at all - you confuse events and non-blocking I/O - the fact that
some data is available does not suddenly make I/O non-blocking. For
that, you need to set your file descriptor to nonblocking (e.g. with
AnyEvent::Util::fh_nonblocking or a platform-specific ioctl/fcntl).
However, note that:
> print <$fh>;
Making the fd non-blockign doesn't mean that you get full lines - for that,
you have to do your own buffering.
Either you do that, or you use some wrapper, scuh as AnyEvent::Handle
(note, this is untested, but should get you going):
my $hdl = new AnyEvent::Handle
fh => $fh,
on_error => sub { ... },
on_read => sub {
my ($hdl) = @_;
$hdl->push_read (line => sub {
my ($hdl, $line) = @_;
say "some data: $line";
});
};
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