AnyEvent/lib/AE.pm

=head1 NAME

AE - simpler/faster/newer/cooler AnyEvent API

=head1 SYNOPSIS

  use AnyEvent; # not AE

  # file handle or descriptor readable
  my $w = AE::io $fh, 0, sub { ...  };

  # one-shot or repeating timers
  my $w = AE::timer $seconds,         0, sub { ... }; # once
  my $w = AE::timer $seconds, $interval, sub { ... }; # repeated

  print AE::now;  # prints current event loop time
  print AE::time; # think Time::HiRes::time or simply CORE::time.

  # POSIX signal
  my $w = AE::signal TERM => sub { ... };

  # child process exit
  my $w = AE::child $pid, sub {
     my ($pid, $status) = @_;
     ...
  };

  # called when event loop idle (if applicable)
  my $w = AE::idle { ... };

  my $w = AE::cv; # stores whether a condition was flagged
  $w->send; # wake up current and all future recv's
  $w->recv; # enters "main loop" till $condvar gets ->send
  # use a condvar in callback mode:
  $w->cb (sub { $_[0]->recv });


=head1 DESCRIPTION

This module documents the new simpler AnyEvent API.

The rationale for the new API is that experience with L<EV> shows that
this API actually "works", despite its lack of extensibility, leading to
a shorter, easier and faster API.

The main differences from AnyEvent is that function calls are used
instead of method calls, and that no named arguments are used.

This makes calls to watcher creation functions really short, which can
make a program more readable despite the lack of named parameters.
Function calls also allow more static type checking than method calls, so
many mistakes are caught at compile-time with this API.

Also, some backends (Perl and EV) are so fast that the method call
overhead is very noticeable (with EV it increases the execution time five-
to six-fold, with Perl the method call overhead is about a factor of two).

At the moment, there is no checking (L<AnyEvent::Strict> does not
affect this API), so the L<AnyEvent> API still has a definite advantage
here.

Note that the C<AE> API is an alternative to, not the future version of,
the AnyEvent API. Both APIs can be used interchangeably and and there are
no plans to "switch", so if in doubt, feel free to use the L<AnyEvent>
API in new code.

As the AE API is complementary, not everything in the AnyEvent API is
available, and you still need to use AnyEvent for the finer stuff. Also,
you should not C<use AE> directly, C<use AnyEvent> will provide the AE
namespace.

=head2 FUNCTIONS

This section briefly describes the alternative watcher
constructors. Semantics are not described here; please
refer to the L<AnyEvent> manpage for the details.

=over 4

=cut

package AE;

use AnyEvent (); # BEGIN { AnyEvent::common_sense }

our $VERSION = $AnyEvent::VERSION;

=item $w = AE::io $fh_or_fd, $watch_write, $cb

Creates an I/O watcher that listens for read events (C<$watch_write>
false) or write events (C<$watch_write> is true) on the file handle or
file descriptor C<$fh_or_fd>.

The callback C<$cb> is invoked as soon and as long as I/O of the type
specified by C<$watch_write>) can be done on the file handle/descriptor.

Example: wait until STDIN becomes readable.

  $stdin_ready = AE::io *STDIN, 0, sub { scalar <STDIN> };

Example: wait until STDOUT becomes writable and print something.

  $stdout_ready = AE::io *STDOUT, 1, sub { print STDOUT "woaw\n" };

=item $w = AE::timer $after, $interval, $cb

Creates a timer watcher that invokes the callback C<$cb> after at least
C<$after> second have passed (C<$after> can be negative or C<0>).

If C<$interval> is C<0>, then the callback will only be invoked once,
otherwise it must be a positive number of seconds that specifies the
interval between successive invocations of the callback.

Example: print "too late" after at least one second has passed.

  $timer_once = AE::timer 1, 0, sub { print "too late\n" };

Example: print "blubb" once a second, starting as soon as possible.

  $timer_repeated = AE::timer 0, 1, sub { print "blubb\n" };

=item $w = AE::signal $signame, $cb

Invoke the callback C<$cb> each time one or more occurrences of the
named signal C<$signame> are detected.

=item $w = AE::child $pid, $cb

Invokes the callback C<$cb> when the child with the given C<$pid> exits
(or all children, when C<$pid> is zero).

The callback will get the actual pid and exit status as arguments.

=item $w = AE::idle $cb

Invoke the callback C<$cb> each time the event loop is "idle" (has no
events outstanding), but do not prevent the event loop from polling for
more events.

=item $cv = AE::cv

=item $cv = AE::cv { BLOCK }

Create a new condition variable. The first form is identical to C<<
AnyEvent->condvar >>, the second form additionally sets the callback (as
if the C<cb> method is called on the condition variable).

=item AE::now

Returns the current event loop time (may be cached by the event loop).

=item AE::now_update

Ensures that the current event loop time is up to date.

=item AE::time

Return the current time (not cached, always consults a hardware clock).

=back

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1

Revision:	1.8
Committed:	Tue Aug 31 00:59:55 2010 UTC (13 years, 10 months ago) by root
Branch:	MAIN
CVS Tags:	rel-5_28, rel-5_29, rel-5_3, rel-5_31
Changes since 1.7:	+19 -19 lines
Log Message:	Message-ID: <20100711085944.GA13997@toroid.org>
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AE - simpler/faster/newer/cooler AnyEvent API
4
5			=head1 SYNOPSIS
6
7	root	1.2	use AnyEvent; # not AE
8	root	1.1
9	root	1.7	# file handle or descriptor readable
10			my $w = AE::io $fh, 0, sub { ... };
11
12			# one-shot or repeating timers
13	root	1.8	my $w = AE::timer $seconds, 0, sub { ... }; # once
14			my $w = AE::timer $seconds, $interval, sub { ... }; # repeated
15	root	1.7
16			print AE::now; # prints current event loop time
17			print AE::time; # think Time::HiRes::time or simply CORE::time.
18
19			# POSIX signal
20			my $w = AE::signal TERM => sub { ... };
21
22			# child process exit
23			my $w = AE::child $pid, sub {
24			my ($pid, $status) = @_;
25			...
26			};
27
28			# called when event loop idle (if applicable)
29			my $w = AE::idle { ... };
30
31			my $w = AE::cv; # stores whether a condition was flagged
32			$w->send; # wake up current and all future recv's
33			$w->recv; # enters "main loop" till $condvar gets ->send
34			# use a condvar in callback mode:
35			$w->cb (sub { $_[0]->recv });
36
37
38	root	1.1	=head1 DESCRIPTION
39
40	root	1.2	This module documents the new simpler AnyEvent API.
41	root	1.1
42			The rationale for the new API is that experience with L<EV> shows that
43	root	1.8	this API actually "works", despite its lack of extensibility, leading to
44	root	1.3	a shorter, easier and faster API.
45	root	1.1
46	root	1.8	The main differences from AnyEvent is that function calls are used
47			instead of method calls, and that no named arguments are used.
48	root	1.2
49			This makes calls to watcher creation functions really short, which can
50	root	1.8	make a program more readable despite the lack of named parameters.
51	root	1.2	Function calls also allow more static type checking than method calls, so
52	root	1.8	many mistakes are caught at compile-time with this API.
53	root	1.2
54			Also, some backends (Perl and EV) are so fast that the method call
55	root	1.6	overhead is very noticeable (with EV it increases the execution time five-
56			to six-fold, with Perl the method call overhead is about a factor of two).
57	root	1.2
58	root	1.8	At the moment, there is no checking (L<AnyEvent::Strict> does not
59			affect this API), so the L<AnyEvent> API still has a definite advantage
60			here.
61	root	1.2
62			Note that the C<AE> API is an alternative to, not the future version of,
63	root	1.8	the AnyEvent API. Both APIs can be used interchangeably and and there are
64	root	1.6	no plans to "switch", so if in doubt, feel free to use the L<AnyEvent>
65			API in new code.
66	root	1.2
67			As the AE API is complementary, not everything in the AnyEvent API is
68	root	1.8	available, and you still need to use AnyEvent for the finer stuff. Also,
69	root	1.2	you should not C<use AE> directly, C<use AnyEvent> will provide the AE
70			namespace.
71
72			=head2 FUNCTIONS
73
74			This section briefly describes the alternative watcher
75	root	1.8	constructors. Semantics are not described here; please
76	root	1.2	refer to the L<AnyEvent> manpage for the details.
77
78			=over 4
79	root	1.1
80			=cut
81
82			package AE;
83
84			use AnyEvent (); # BEGIN { AnyEvent::common_sense }
85
86	root	1.4	our $VERSION = $AnyEvent::VERSION;
87
88	root	1.2	=item $w = AE::io $fh_or_fd, $watch_write, $cb
89
90			Creates an I/O watcher that listens for read events (C<$watch_write>
91			false) or write events (C<$watch_write> is true) on the file handle or
92			file descriptor C<$fh_or_fd>.
93
94			The callback C<$cb> is invoked as soon and as long as I/O of the type
95			specified by C<$watch_write>) can be done on the file handle/descriptor.
96
97			Example: wait until STDIN becomes readable.
98
99			$stdin_ready = AE::io *STDIN, 0, sub { scalar <STDIN> };
100
101	root	1.8	Example: wait until STDOUT becomes writable and print something.
102	root	1.2
103			$stdout_ready = AE::io *STDOUT, 1, sub { print STDOUT "woaw\n" };
104
105			=item $w = AE::timer $after, $interval, $cb
106
107			Creates a timer watcher that invokes the callback C<$cb> after at least
108			C<$after> second have passed (C<$after> can be negative or C<0>).
109
110	root	1.8	If C<$interval> is C<0>, then the callback will only be invoked once,
111			otherwise it must be a positive number of seconds that specifies the
112	root	1.2	interval between successive invocations of the callback.
113
114			Example: print "too late" after at least one second has passed.
115
116			$timer_once = AE::timer 1, 0, sub { print "too late\n" };
117
118			Example: print "blubb" once a second, starting as soon as possible.
119
120			$timer_repeated = AE::timer 0, 1, sub { print "blubb\n" };
121
122			=item $w = AE::signal $signame, $cb
123
124	root	1.8	Invoke the callback C<$cb> each time one or more occurrences of the
125			named signal C<$signame> are detected.
126	root	1.2
127			=item $w = AE::child $pid, $cb
128
129	root	1.8	Invokes the callback C<$cb> when the child with the given C<$pid> exits
130	root	1.2	(or all children, when C<$pid> is zero).
131
132			The callback will get the actual pid and exit status as arguments.
133
134			=item $w = AE::idle $cb
135
136			Invoke the callback C<$cb> each time the event loop is "idle" (has no
137			events outstanding), but do not prevent the event loop from polling for
138			more events.
139
140			=item $cv = AE::cv
141
142			=item $cv = AE::cv { BLOCK }
143
144			Create a new condition variable. The first form is identical to C<<
145			AnyEvent->condvar >>, the second form additionally sets the callback (as
146			if the C<cb> method is called on the condition variable).
147
148			=item AE::now
149
150			Returns the current event loop time (may be cached by the event loop).
151
152			=item AE::now_update
153
154			Ensures that the current event loop time is up to date.
155
156			=item AE::time
157
158			Return the current time (not cached, always consults a hardware clock).
159
160			=back
161	root	1.1
162			=head1 AUTHOR
163
164			Marc Lehmann <schmorp@schmorp.de>
165			http://home.schmorp.de/
166
167			=cut
168
169	root	1.2	1
170