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Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.271 by root, Fri Oct 2 19:55:59 2009 UTC vs.
Revision 1.282 by root, Sun Dec 26 16:23:51 2010 UTC

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81 81
82our $idle; # idle handler 82our $idle; # idle handler
83our $main; # main coro 83our $main; # main coro
84our $current; # current coro 84our $current; # current coro
85 85
86our $VERSION = 5.2; 86our $VERSION = 5.25;
87 87
88our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); 88our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait);
89our %EXPORT_TAGS = ( 89our %EXPORT_TAGS = (
90 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 90 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
91); 91);
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138 138
139See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. 139See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique.
140 140
141=cut 141=cut
142 142
143# ||= because other modules could have provided their own by now
143$idle = new Coro sub { 144$idle ||= new Coro sub {
144 require Coro::Debug; 145 require Coro::Debug;
145 die "FATAL: deadlock detected.\n" 146 die "FATAL: deadlock detected.\n"
146 . Coro::Debug::ps_listing (); 147 . Coro::Debug::ps_listing ();
147}; 148};
148 149
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612Sets (or gets in case the argument is missing) the description for this 613Sets (or gets in case the argument is missing) the description for this
613coro. This is just a free-form string you can associate with a 614coro. This is just a free-form string you can associate with a
614coro. 615coro.
615 616
616This method simply sets the C<< $coro->{desc} >> member to the given 617This method simply sets the C<< $coro->{desc} >> member to the given
617string. You can modify this member directly if you wish. 618string. You can modify this member directly if you wish, and in fact, this
619is often preferred to indicate major processing states that cna then be
620seen for example in a L<Coro::Debug> session:
621
622 sub my_long_function {
623 local $Coro::current->{desc} = "now in my_long_function";
624 ...
625 $Coro::current->{desc} = "my_long_function: phase 1";
626 ...
627 $Coro::current->{desc} = "my_long_function: phase 2";
628 ...
629 }
618 630
619=cut 631=cut
620 632
621sub desc { 633sub desc {
622 my $old = $_[0]{desc}; 634 my $old = $_[0]{desc};
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659returning a new coderef. Unblocking means that calling the new coderef 671returning a new coderef. Unblocking means that calling the new coderef
660will return immediately without blocking, returning nothing, while the 672will return immediately without blocking, returning nothing, while the
661original code ref will be called (with parameters) from within another 673original code ref will be called (with parameters) from within another
662coro. 674coro.
663 675
664The reason this function exists is that many event libraries (such as the 676The reason this function exists is that many event libraries (such as
665venerable L<Event|Event> module) are not thread-safe (a weaker form 677the venerable L<Event|Event> module) are not thread-safe (a weaker form
666of reentrancy). This means you must not block within event callbacks, 678of reentrancy). This means you must not block within event callbacks,
667otherwise you might suffer from crashes or worse. The only event library 679otherwise you might suffer from crashes or worse. The only event library
668currently known that is safe to use without C<unblock_sub> is L<EV>. 680currently known that is safe to use without C<unblock_sub> is L<EV> (but
681you might still run into deadlocks if all event loops are blocked).
682
683Coro will try to catch you when you block in the event loop
684("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and
685only works when you do not run your own event loop.
669 686
670This function allows your callbacks to block by executing them in another 687This function allows your callbacks to block by executing them in another
671coro where it is safe to block. One example where blocking is handy 688coro where it is safe to block. One example where blocking is handy
672is when you use the L<Coro::AIO|Coro::AIO> functions to save results to 689is when you use the L<Coro::AIO|Coro::AIO> functions to save results to
673disk, for example. 690disk, for example.
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830the windows process emulation enabled under unix roughly halves perl 847the windows process emulation enabled under unix roughly halves perl
831performance, even when not used. 848performance, even when not used.
832 849
833=item coro switching is not signal safe 850=item coro switching is not signal safe
834 851
835You must not switch to another coro from within a signal handler 852You must not switch to another coro from within a signal handler (only
836(only relevant with %SIG - most event libraries provide safe signals). 853relevant with %SIG - most event libraries provide safe signals), I<unless>
854you are sure you are not interrupting a Coro function.
837 855
838That means you I<MUST NOT> call any function that might "block" the 856That means you I<MUST NOT> call any function that might "block" the
839current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or 857current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
840anything that calls those. Everything else, including calling C<ready>, 858anything that calls those. Everything else, including calling C<ready>,
841works. 859works.
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851ithreads (for example, that memory or files would be shared), showing his 869ithreads (for example, that memory or files would be shared), showing his
852lack of understanding of this area - if it is hard to understand for Chip, 870lack of understanding of this area - if it is hard to understand for Chip,
853it is probably not obvious to everybody). 871it is probably not obvious to everybody).
854 872
855What follows is an ultra-condensed version of my talk about threads in 873What follows is an ultra-condensed version of my talk about threads in
856scripting languages given onthe perl workshop 2009: 874scripting languages given on the perl workshop 2009:
857 875
858The so-called "ithreads" were originally implemented for two reasons: 876The so-called "ithreads" were originally implemented for two reasons:
859first, to (badly) emulate unix processes on native win32 perls, and 877first, to (badly) emulate unix processes on native win32 perls, and
860secondly, to replace the older, real thread model ("5.005-threads"). 878secondly, to replace the older, real thread model ("5.005-threads").
861 879

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