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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.100 by root, Thu Oct 23 02:44:50 2008 UTC vs.
Revision 1.101 by root, Thu Oct 23 19:03:30 2008 UTC

84Set the callback to be called when an end-of-file condition is detected, 84Set the callback to be called when an end-of-file condition is detected,
85i.e. in the case of a socket, when the other side has closed the 85i.e. in the case of a socket, when the other side has closed the
86connection cleanly. 86connection cleanly.
87 87
88For sockets, this just means that the other side has stopped sending data, 88For sockets, this just means that the other side has stopped sending data,
89you can still try to write data, and, in fact, one can return from the eof 89you can still try to write data, and, in fact, one can return from the EOF
90callback and continue writing data, as only the read part has been shut 90callback and continue writing data, as only the read part has been shut
91down. 91down.
92 92
93While not mandatory, it is I<highly> recommended to set an eof callback, 93While not mandatory, it is I<highly> recommended to set an EOF callback,
94otherwise you might end up with a closed socket while you are still 94otherwise you might end up with a closed socket while you are still
95waiting for data. 95waiting for data.
96 96
97If an EOF condition has been detected but no C<on_eof> callback has been 97If an EOF condition has been detected but no C<on_eof> callback has been
98set, then a fatal error will be raised with C<$!> set to <0>. 98set, then a fatal error will be raised with C<$!> set to <0>.
1472 } 1472 }
1473} 1473}
1474 1474
1475=item $handle->destroy 1475=item $handle->destroy
1476 1476
1477Shut's down the handle object as much as possible - this call ensures that 1477Shuts down the handle object as much as possible - this call ensures that
1478no further callbacks will be invoked and resources will be freed as much 1478no further callbacks will be invoked and resources will be freed as much
1479as possible. You must not call any methods on the object afterwards. 1479as possible. You must not call any methods on the object afterwards.
1480
1481Normally, you can just "forget" any references to an AnyEvent::Handle
1482object and it will simply shut down. This works in fatal error and EOF
1483callbacks, as well as code outside. It does I<NOT> work in a read or write
1484callback, so when you want to destroy the AnyEvent::Handle object from
1485within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
1486that case.
1480 1487
1481The handle might still linger in the background and write out remaining 1488The handle might still linger in the background and write out remaining
1482data, as specified by the C<linger> option, however. 1489data, as specified by the C<linger> option, however.
1483 1490
1484=cut 1491=cut
1529 1536
1530 1537
1531=head1 NONFREQUENTLY ASKED QUESTIONS 1538=head1 NONFREQUENTLY ASKED QUESTIONS
1532 1539
1533=over 4 1540=over 4
1541
1542=item I C<undef> the AnyEvent::Handle reference inside my callback and
1543still get further invocations!
1544
1545That's because AnyEvent::Handle keeps a reference to itself when handling
1546read or write callbacks.
1547
1548It is only safe to "forget" the reference inside EOF or error callbacks,
1549from within all other callbacks, you need to explicitly call the C<<
1550->destroy >> method.
1551
1552=item I get different callback invocations in TLS mode/Why can't I pause
1553reading?
1554
1555Unlike, say, TCP, TLS connections do not consist of two independent
1556communication channels, one for each direction. Or put differently. The
1557read and write directions are not independent of each other: you cannot
1558write data unless you are also prepared to read, and vice versa.
1559
1560This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
1561callback invocations when you are not expecting any read data - the reason
1562is that AnyEvent::Handle always reads in TLS mode.
1563
1564During the connection, you have to make sure that you always have a
1565non-empty read-queue, or an C<on_read> watcher. At the end of the
1566connection (or when you no longer want to use it) you can call the
1567C<destroy> method.
1534 1568
1535=item How do I read data until the other side closes the connection? 1569=item How do I read data until the other side closes the connection?
1536 1570
1537If you just want to read your data into a perl scalar, the easiest way 1571If you just want to read your data into a perl scalar, the easiest way
1538to achieve this is by setting an C<on_read> callback that does nothing, 1572to achieve this is by setting an C<on_read> callback that does nothing,
1548 1582
1549The reason to use C<on_error> is that TCP connections, due to latencies 1583The reason to use C<on_error> is that TCP connections, due to latencies
1550and packets loss, might get closed quite violently with an error, when in 1584and packets loss, might get closed quite violently with an error, when in
1551fact, all data has been received. 1585fact, all data has been received.
1552 1586
1553It is usually better to use acknowledgements when transfering data, 1587It is usually better to use acknowledgements when transferring data,
1554to make sure the other side hasn't just died and you got the data 1588to make sure the other side hasn't just died and you got the data
1555intact. This is also one reason why so many internet protocols have an 1589intact. This is also one reason why so many internet protocols have an
1556explicit QUIT command. 1590explicit QUIT command.
1557
1558 1591
1559=item I don't want to destroy the handle too early - how do I wait until 1592=item I don't want to destroy the handle too early - how do I wait until
1560all data has been written? 1593all data has been written?
1561 1594
1562After writing your last bits of data, set the C<on_drain> callback 1595After writing your last bits of data, set the C<on_drain> callback
1568 $handle->on_drain (sub { 1601 $handle->on_drain (sub {
1569 warn "all data submitted to the kernel\n"; 1602 warn "all data submitted to the kernel\n";
1570 undef $handle; 1603 undef $handle;
1571 }); 1604 });
1572 1605
1573=item I get different callback invocations in TLS mode/Why can't I pause
1574reading?
1575
1576Unlike, say, TCP, TLS conenctions do not consist of two independent
1577communication channels, one for each direction. Or put differently. the
1578read and write directions are not independent of each other: you cannot
1579write data unless you are also prepared to read, and vice versa.
1580
1581This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
1582callback invocations when you are not expecting any read data - the reason
1583is that AnyEvent::Handle always reads in TLS mode.
1584
1585During the connection, you have to make sure that you always have a
1586non-empty read-queue, or an C<on_read> watcher. At the end of the
1587connection (or when you no longer want to use it) you can call the
1588C<destroy> method.
1589
1590=back 1606=back
1591 1607
1592 1608
1593=head1 SUBCLASSING AnyEvent::Handle 1609=head1 SUBCLASSING AnyEvent::Handle
1594 1610

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