| … | |
… | |
| 661 | if the thread is inside a C callback that doesn't expect to be |
661 | if the thread is inside a C callback that doesn't expect to be |
| 662 | canceled, bad things can happen, or if the cancelled thread insists |
662 | canceled, bad things can happen, or if the cancelled thread insists |
| 663 | on running complicated cleanup handlers that rely on its thread |
663 | on running complicated cleanup handlers that rely on its thread |
| 664 | context, things will not work. |
664 | context, things will not work. |
| 665 | |
665 | |
| 666 | Any cleanup code being run (e.g. from "guard" blocks) will be run |
666 | Any cleanup code being run (e.g. from "guard" blocks, destructors |
| 667 | without a thread context, and is not allowed to switch to other |
667 | and so on) will be run without a thread context, and is not allowed |
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|
668 | to switch to other threads. A common mistake is to call "->cancel" |
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|
669 | from a destructor called by die'ing inside the thread to be |
|
|
670 | cancelled for example. |
|
|
671 | |
| 668 | threads. On the plus side, "->cancel" will always clean up the |
672 | On the plus side, "->cancel" will always clean up the thread, no |
| 669 | thread, no matter what. If your cleanup code is complex or you want |
673 | matter what. If your cleanup code is complex or you want to avoid |
| 670 | to avoid cancelling a C-thread that doesn't know how to clean up |
674 | cancelling a C-thread that doesn't know how to clean up itself, it |
| 671 | itself, it can be better to "->throw" an exception, or use |
675 | can be better to "->throw" an exception, or use "->safe_cancel". |
| 672 | "->safe_cancel". |
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|
| 673 | |
676 | |
| 674 | The arguments to "->cancel" are not copied, but instead will be |
677 | The arguments to "->cancel" are not copied, but instead will be |
| 675 | referenced directly (e.g. if you pass $var and after the call change |
678 | referenced directly (e.g. if you pass $var and after the call change |
| 676 | that variable, then you might change the return values passed to |
679 | that variable, then you might change the return values passed to |
| 677 | e.g. "join", so don't do that). |
680 | e.g. "join", so don't do that). |
| … | |
… | |
| 682 | actually destruct the Coro object. |
685 | actually destruct the Coro object. |
| 683 | |
686 | |
| 684 | $coro->safe_cancel ($arg...) |
687 | $coro->safe_cancel ($arg...) |
| 685 | Works mostly like "->cancel", but is inherently "safer", and |
688 | Works mostly like "->cancel", but is inherently "safer", and |
| 686 | consequently, can fail with an exception in cases the thread is not |
689 | consequently, can fail with an exception in cases the thread is not |
| 687 | in a cancellable state. |
690 | in a cancellable state. Essentially, "->safe_cancel" is a "->cancel" |
|
|
691 | with extra checks before canceling. |
| 688 | |
692 | |
| 689 | This method works a bit like throwing an exception that cannot be |
693 | It works a bit like throwing an exception that cannot be caught - |
| 690 | caught - specifically, it will clean up the thread from within |
694 | specifically, it will clean up the thread from within itself, so all |
| 691 | itself, so all cleanup handlers (e.g. "guard" blocks) are run with |
695 | cleanup handlers (e.g. "guard" blocks) are run with full thread |
| 692 | full thread context and can block if they wish. The downside is that |
696 | context and can block if they wish. The downside is that there is no |
| 693 | there is no guarantee that the thread can be cancelled when you call |
697 | guarantee that the thread can be cancelled when you call this |
| 694 | this method, and therefore, it might fail. It is also considerably |
698 | method, and therefore, it might fail. It is also considerably slower |
| 695 | slower than "cancel" or "terminate". |
699 | than "cancel" or "terminate". |
| 696 | |
700 | |
| 697 | A thread is in a safe-cancellable state if it either hasn't been run |
701 | A thread is in a safe-cancellable state if it either hasn't been run |
| 698 | yet, or it has no C context attached and is inside an SLF function. |
702 | yet, or it has no C context attached and is inside an SLF function. |
| 699 | |
703 | |
| 700 | The latter two basically mean that the thread isn't currently inside |
704 | The latter two basically mean that the thread isn't currently inside |
