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Revision 1.129 by elmex, Sat May 24 15:19:30 2008 UTC vs.
Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC

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311>> method, usually without arguments. The only argument pair allowed is 311>> method, usually without arguments. The only argument pair allowed is
312C<cb>, which specifies a callback to be called when the condition variable 312C<cb>, which specifies a callback to be called when the condition variable
313becomes true. 313becomes true.
314 314
315After creation, the condition variable is "false" until it becomes "true" 315After creation, the condition variable is "false" until it becomes "true"
316by calling the C<send> method. 316by calling the C<send> method (or calling the condition variable as if it
317were a callback).
317 318
318Condition variables are similar to callbacks, except that you can 319Condition variables are similar to callbacks, except that you can
319optionally wait for them. They can also be called merge points - points 320optionally wait for them. They can also be called merge points - points
320in time where multiple outstanding events have been processed. And yet 321in time where multiple outstanding events have been processed. And yet
321another way to call them is transactions - each condition variable can be 322another way to call them is transactions - each condition variable can be
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347 348
348There are two "sides" to a condition variable - the "producer side" which 349There are two "sides" to a condition variable - the "producer side" which
349eventually calls C<< -> send >>, and the "consumer side", which waits 350eventually calls C<< -> send >>, and the "consumer side", which waits
350for the send to occur. 351for the send to occur.
351 352
352Example: 353Example: wait for a timer.
353 354
354 # wait till the result is ready 355 # wait till the result is ready
355 my $result_ready = AnyEvent->condvar; 356 my $result_ready = AnyEvent->condvar;
356 357
357 # do something such as adding a timer 358 # do something such as adding a timer
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365 366
366 # this "blocks" (while handling events) till the callback 367 # this "blocks" (while handling events) till the callback
367 # calls send 368 # calls send
368 $result_ready->recv; 369 $result_ready->recv;
369 370
371Example: wait for a timer, but take advantage of the fact that
372condition variables are also code references.
373
374 my $done = AnyEvent->condvar;
375 my $delay = AnyEvent->timer (after => 5, cb => $done);
376 $done->recv;
377
370=head3 METHODS FOR PRODUCERS 378=head3 METHODS FOR PRODUCERS
371 379
372These methods should only be used by the producing side, i.e. the 380These methods should only be used by the producing side, i.e. the
373code/module that eventually sends the signal. Note that it is also 381code/module that eventually sends the signal. Note that it is also
374the producer side which creates the condvar in most cases, but it isn't 382the producer side which creates the condvar in most cases, but it isn't
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385If a callback has been set on the condition variable, it is called 393If a callback has been set on the condition variable, it is called
386immediately from within send. 394immediately from within send.
387 395
388Any arguments passed to the C<send> call will be returned by all 396Any arguments passed to the C<send> call will be returned by all
389future C<< ->recv >> calls. 397future C<< ->recv >> calls.
398
399Condition variables are overloaded so one can call them directly (as a
400code reference). Calling them directly is the same as calling C<send>.
390 401
391=item $cv->croak ($error) 402=item $cv->croak ($error)
392 403
393Similar to send, but causes all call's to C<< ->recv >> to invoke 404Similar to send, but causes all call's to C<< ->recv >> to invoke
394C<Carp::croak> with the given error message/object/scalar. 405C<Carp::croak> with the given error message/object/scalar.
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508The callback will be called when the condition becomes "true", i.e. when 519The callback will be called when the condition becomes "true", i.e. when
509C<send> or C<croak> are called. Calling C<recv> inside the callback 520C<send> or C<croak> are called. Calling C<recv> inside the callback
510or at any later time is guaranteed not to block. 521or at any later time is guaranteed not to block.
511 522
512=back 523=back
524
525=head3 MAINLOOP EMULATION
526
527Sometimes (often for short test scripts, or even standalone programs
528who only want to use AnyEvent), you I<do> want your program to block
529indefinitely in some event loop.
530
531In that case, you cna use a condition variable like this:
532
533 AnyEvent->condvar->recv;
534
535This has the effect of entering the event loop and looping forever.
536
537Note that usually your program has some exit condition, in which case
538it is better to use the "traditional" approach of storing a condition
539variable, waiting for it, and sending it when the program should exit
540cleanly.
541
513 542
514=head1 GLOBAL VARIABLES AND FUNCTIONS 543=head1 GLOBAL VARIABLES AND FUNCTIONS
515 544
516=over 4 545=over 4
517 546
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696no warnings; 725no warnings;
697use strict; 726use strict;
698 727
699use Carp; 728use Carp;
700 729
701our $VERSION = '3.6'; 730our $VERSION = '4.03';
702our $MODEL; 731our $MODEL;
703 732
704our $AUTOLOAD; 733our $AUTOLOAD;
705our @ISA; 734our @ISA;
706 735
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914 943
915our @ISA = AnyEvent::CondVar::Base::; 944our @ISA = AnyEvent::CondVar::Base::;
916 945
917package AnyEvent::CondVar::Base; 946package AnyEvent::CondVar::Base;
918 947
948use overload
949 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
950 fallback => 1;
951
919sub _send { 952sub _send {
920 # nop 953 # nop
921} 954}
922 955
923sub send { 956sub send {

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