… | |
… | |
90 | } 1, 2, 3; |
90 | } 1, 2, 3; |
91 | |
91 | |
92 | This creates a new coro thread and puts it into the ready queue, meaning |
92 | This creates a new coro thread and puts it into the ready queue, meaning |
93 | it will run as soon as the CPU is free for it. |
93 | it will run as soon as the CPU is free for it. |
94 | |
94 | |
95 | C<async> will return a coro object - you can store this for future |
95 | C<async> will return a Coro object - you can store this for future |
96 | reference or ignore it, the thread itself will keep a reference to it's |
96 | reference or ignore it - a thread that is running, ready to run or waiting |
97 | thread object - threads are alive on their own. |
97 | for some event is alive on it's own. |
98 | |
98 | |
99 | Another way to create a thread is to call the C<new> constructor with a |
99 | Another way to create a thread is to call the C<new> constructor with a |
100 | code-reference: |
100 | code-reference: |
101 | |
101 | |
102 | new Coro sub { |
102 | new Coro sub { |
… | |
… | |
131 | A lot can happen after the coro thread has started running. Quite usually, |
131 | A lot can happen after the coro thread has started running. Quite usually, |
132 | it will not run to the end in one go (because you could use a function |
132 | it will not run to the end in one go (because you could use a function |
133 | instead), but it will give up the CPU regularly because it waits for |
133 | instead), but it will give up the CPU regularly because it waits for |
134 | external events. |
134 | external events. |
135 | |
135 | |
136 | As long as a coro thread runs, it's coro object is available in the global |
136 | As long as a coro thread runs, its Coro object is available in the global |
137 | variable C<$Coro::current>. |
137 | variable C<$Coro::current>. |
138 | |
138 | |
139 | The low-level way to give up the CPU is to call the scheduler, which |
139 | The low-level way to give up the CPU is to call the scheduler, which |
140 | selects a new coro thread to run: |
140 | selects a new coro thread to run: |
141 | |
141 | |
… | |
… | |
219 | So, cancelling a thread that runs in an XS event loop might not be the |
219 | So, cancelling a thread that runs in an XS event loop might not be the |
220 | best idea, but any other combination that deals with perl only (cancelling |
220 | best idea, but any other combination that deals with perl only (cancelling |
221 | when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is |
221 | when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is |
222 | safe. |
222 | safe. |
223 | |
223 | |
|
|
224 | Lastly, a coro thread object that isn't referenced is C<< ->cancel >>'ed |
|
|
225 | automatically - just like other objects in Perl. This is not such a common |
|
|
226 | case, however - a running thread is referencedy b C<$Coro::current>, a |
|
|
227 | thread ready to run is referenced by the ready queue, a thread waiting |
|
|
228 | on a lock or semaphore is referenced by being in some wait list and so |
|
|
229 | on. But a thread that isn't in any of those queues gets cancelled: |
|
|
230 | |
|
|
231 | async { |
|
|
232 | schedule; # cede to other coros, don't go into the ready queue |
|
|
233 | }; |
|
|
234 | |
|
|
235 | cede; |
|
|
236 | # now the async above is destroyed, as it is not referenced by anything. |
|
|
237 | |
224 | =item 5. Cleanup |
238 | =item 5. Cleanup |
225 | |
239 | |
226 | Threads will allocate various resources. Most but not all will be returned |
240 | Threads will allocate various resources. Most but not all will be returned |
227 | when a thread terminates, during clean-up. |
241 | when a thread terminates, during clean-up. |
228 | |
242 | |
… | |
… | |
251 | # if we reutrn, or die or get cancelled, here, |
265 | # if we reutrn, or die or get cancelled, here, |
252 | # then the semaphore will be "up"ed. |
266 | # then the semaphore will be "up"ed. |
253 | }; |
267 | }; |
254 | |
268 | |
255 | The C<Guard::guard> function comes in handy for any custom cleanup you |
269 | The C<Guard::guard> function comes in handy for any custom cleanup you |
256 | might want to do: |
270 | might want to do (but you cannot switch to other coroutines form those |
|
|
271 | code blocks): |
257 | |
272 | |
258 | async { |
273 | async { |
259 | my $window = new Gtk2::Window "toplevel"; |
274 | my $window = new Gtk2::Window "toplevel"; |
260 | # The window will not be cleaned up automatically, even when $window |
275 | # The window will not be cleaned up automatically, even when $window |
261 | # gets freed, so use a guard to ensure it's destruction |
276 | # gets freed, so use a guard to ensure it's destruction |
… | |
… | |
274 | # if we return or die here, the description will be restored |
289 | # if we return or die here, the description will be restored |
275 | } |
290 | } |
276 | |
291 | |
277 | =item 6. Viva La Zombie Muerte |
292 | =item 6. Viva La Zombie Muerte |
278 | |
293 | |
279 | Even after a thread has terminated and cleaned up it's resources, the coro |
294 | Even after a thread has terminated and cleaned up its resources, the Coro |
280 | object still is there and stores the return values of the thread. Only in |
295 | object still is there and stores the return values of the thread. |
281 | this state will the coro object be "reference counted" in the normal perl |
|
|
282 | sense: the thread code keeps a reference to it when it is active, but not |
|
|
283 | after it has terminated. |
|
|
284 | |
296 | |
285 | The means the coro object gets freed automatically when the thread has |
297 | The means the Coro object gets freed automatically when the thread has |
286 | terminated and cleaned up and there arenot other references. |
298 | terminated and cleaned up and there arenot other references. |
287 | |
299 | |
288 | If there are, the coro object will stay around, and you can call C<< |
300 | If there are, the Coro object will stay around, and you can call C<< |
289 | ->join >> as many times as you wish to retrieve the result values: |
301 | ->join >> as many times as you wish to retrieve the result values: |
290 | |
302 | |
291 | async { |
303 | async { |
292 | print "hi\n"; |
304 | print "hi\n"; |
293 | 1 |
305 | 1 |
… | |
… | |
713 | To avoid this, it is best to put a suspended coro into the ready queue |
725 | To avoid this, it is best to put a suspended coro into the ready queue |
714 | unconditionally, as every synchronisation mechanism must protect itself |
726 | unconditionally, as every synchronisation mechanism must protect itself |
715 | against spurious wakeups, and the one in the Coro family certainly do |
727 | against spurious wakeups, and the one in the Coro family certainly do |
716 | that. |
728 | that. |
717 | |
729 | |
|
|
730 | =item $state->is_new |
|
|
731 | |
|
|
732 | Returns true iff this Coro object is "new", i.e. has never been run |
|
|
733 | yet. Those states basically consist of only the code reference to call and |
|
|
734 | the arguments, but consumes very little other resources. New states will |
|
|
735 | automatically get assigned a perl interpreter when they are transfered to. |
|
|
736 | |
|
|
737 | =item $state->is_zombie |
|
|
738 | |
|
|
739 | Returns true iff the Coro object has been cancelled, i.e. |
|
|
740 | it's resources freed because they were C<cancel>'ed, C<terminate>'d, |
|
|
741 | C<safe_cancel>'ed or simply went out of scope. |
|
|
742 | |
|
|
743 | The name "zombie" stems from UNIX culture, where a process that has |
|
|
744 | exited and only stores and exit status and no other resources is called a |
|
|
745 | "zombie". |
|
|
746 | |
718 | =item $is_ready = $coro->is_ready |
747 | =item $is_ready = $coro->is_ready |
719 | |
748 | |
720 | Returns true iff the Coro object is in the ready queue. Unless the Coro |
749 | Returns true iff the Coro object is in the ready queue. Unless the Coro |
721 | object gets destroyed, it will eventually be scheduled by the scheduler. |
750 | object gets destroyed, it will eventually be scheduled by the scheduler. |
722 | |
751 | |
… | |
… | |
854 | Wait until the coro terminates and return any values given to the |
883 | Wait until the coro terminates and return any values given to the |
855 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
884 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
856 | from multiple threads, and all will be resumed and given the status |
885 | from multiple threads, and all will be resumed and given the status |
857 | return once the C<$coro> terminates. |
886 | return once the C<$coro> terminates. |
858 | |
887 | |
859 | =cut |
|
|
860 | |
|
|
861 | sub join { |
|
|
862 | my $self = shift; |
|
|
863 | |
|
|
864 | unless ($self->{_status}) { |
|
|
865 | my $current = $current; |
|
|
866 | |
|
|
867 | push @{$self->{_on_destroy}}, sub { |
|
|
868 | $current->ready; |
|
|
869 | undef $current; |
|
|
870 | }; |
|
|
871 | |
|
|
872 | &schedule while $current; |
|
|
873 | } |
|
|
874 | |
|
|
875 | wantarray ? @{$self->{_status}} : $self->{_status}[0] |
|
|
876 | } |
|
|
877 | |
|
|
878 | =item $coro->on_destroy (\&cb) |
888 | =item $coro->on_destroy (\&cb) |
879 | |
889 | |
880 | Registers a callback that is called when this coro thread gets destroyed, |
890 | Registers a callback that is called when this coro thread gets destroyed, |
881 | that is, after it's resources have been freed but before it is joined. The |
891 | that is, after it's resources have been freed but before it is joined. The |
882 | callback gets passed the terminate/cancel arguments, if any, and I<must |
892 | callback gets passed the terminate/cancel arguments, if any, and I<must |
883 | not> die, under any circumstances. |
893 | not> die, under any circumstances. |
884 | |
894 | |
885 | There can be any number of C<on_destroy> callbacks per coro, and there is |
895 | There can be any number of C<on_destroy> callbacks per coro, and there is |
886 | no way currently to remove a callback once added. |
896 | no way currently to remove a callback once added. |
887 | |
|
|
888 | =cut |
|
|
889 | |
|
|
890 | sub on_destroy { |
|
|
891 | my ($self, $cb) = @_; |
|
|
892 | |
|
|
893 | push @{ $self->{_on_destroy} }, $cb; |
|
|
894 | } |
|
|
895 | |
897 | |
896 | =item $oldprio = $coro->prio ($newprio) |
898 | =item $oldprio = $coro->prio ($newprio) |
897 | |
899 | |
898 | Sets (or gets, if the argument is missing) the priority of the |
900 | Sets (or gets, if the argument is missing) the priority of the |
899 | coro thread. Higher priority coro get run before lower priority |
901 | coro thread. Higher priority coro get run before lower priority |
… | |
… | |
1171 | future to allow per-thread schedulers, but Coro::State does not yet allow |
1173 | future to allow per-thread schedulers, but Coro::State does not yet allow |
1172 | this). I recommend disabling thread support and using processes, as having |
1174 | this). I recommend disabling thread support and using processes, as having |
1173 | the windows process emulation enabled under unix roughly halves perl |
1175 | the windows process emulation enabled under unix roughly halves perl |
1174 | performance, even when not used. |
1176 | performance, even when not used. |
1175 | |
1177 | |
|
|
1178 | Attempts to use threads created in another emulated process will crash |
|
|
1179 | ("cleanly", with a null pointer exception). |
|
|
1180 | |
1176 | =item coro switching is not signal safe |
1181 | =item coro switching is not signal safe |
1177 | |
1182 | |
1178 | You must not switch to another coro from within a signal handler (only |
1183 | You must not switch to another coro from within a signal handler (only |
1179 | relevant with %SIG - most event libraries provide safe signals), I<unless> |
1184 | relevant with %SIG - most event libraries provide safe signals), I<unless> |
1180 | you are sure you are not interrupting a Coro function. |
1185 | you are sure you are not interrupting a Coro function. |