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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC vs.
Revision 1.229 by root, Wed Jul 8 02:01:12 2009 UTC

… …
176=head2 I/O WATCHERS 176=head2 I/O WATCHERS
177 177
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 178You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
180 180
181C<fh> is the Perl I<file handle> (I<not> file descriptor, see below) to 181C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182watch for events (AnyEvent might or might not keep a reference to this 182for events (AnyEvent might or might not keep a reference to this file
183file handle). Note that only file handles pointing to things for which 183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 185most character devices, pipes, fifos and so on, but not for example files
186or block devices. 186or block devices.
187 187
188C<poll> must be a string that is either C<r> or C<w>, which creates a 188C<poll> must be a string that is either C<r> or C<w>, which creates a
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208 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 208 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
209 chomp (my $input = <STDIN>); 209 chomp (my $input = <STDIN>);
210 warn "read: $input\n"; 210 warn "read: $input\n";
211 undef $w; 211 undef $w;
212 }); 212 });
213
214=head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR
215
216It is not uncommon to only have a file descriptor, while AnyEvent requires
217a Perl file handle.
218
219There are basically two methods to convert a file descriptor into a file handle. If you own
220the file descriptor, you can open it with C<&=>, as in:
221
222 open my $fh, "<&=$fileno" or die "xxx: ยง!";
223
224This will "own" the file descriptor, meaning that when C<$fh> is
225destroyed, it will automatically close the C<$fileno>. Also, note that
226the open mode (read, write, read/write) must correspond with how the
227underlying file descriptor was opened.
228
229In many cases, taking over the file descriptor is now what you want, in
230which case the only alternative is to dup the file descriptor:
231
232 open my $fh, "<&$fileno" or die "xxx: $!";
233
234This has the advantage of not closing the file descriptor and the
235disadvantage of making a slow copy.
236 213
237=head2 TIME WATCHERS 214=head2 TIME WATCHERS
238 215
239You can create a time watcher by calling the C<< AnyEvent->timer >> 216You can create a time watcher by calling the C<< AnyEvent->timer >>
240method with the following mandatory arguments: 217method with the following mandatory arguments:
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1146# allow only one watcher per fd, so we dup it to get a different one). 1123# allow only one watcher per fd, so we dup it to get a different one).
1147sub _dupfh($$;$$) { 1124sub _dupfh($$;$$) {
1148 my ($poll, $fh, $r, $w) = @_; 1125 my ($poll, $fh, $r, $w) = @_;
1149 1126
1150 # cygwin requires the fh mode to be matching, unix doesn't 1127 # cygwin requires the fh mode to be matching, unix doesn't
1151 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1128 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
1152 : $poll eq "w" ? ($w, ">")
1153 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1154 1129
1155 open my $fh2, "$mode&" . fileno $fh 1130 open my $fh2, "$mode&", $fh
1156 or die "cannot dup() filehandle: $!,"; 1131 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1157 1132
1158 # we assume CLOEXEC is already set by perl in all important cases 1133 # we assume CLOEXEC is already set by perl in all important cases
1159 1134
1160 ($fh2, $rw) 1135 ($fh2, $rw)
1161} 1136}

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