| … | |
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| 17 | cede; |
17 | cede; |
| 18 | |
18 | |
| 19 | DESCRIPTION |
19 | DESCRIPTION |
| 20 | This module collection manages coroutines. Coroutines are similar to |
20 | This module collection manages coroutines. Coroutines are similar to |
| 21 | threads but don't run in parallel at the same time even on SMP machines. |
21 | threads but don't run in parallel at the same time even on SMP machines. |
| 22 | The specific flavor of coroutine use din this module also guarentees you |
22 | The specific flavor of coroutine used in this module also guarantees you |
| 23 | that it will not switch between coroutines unless necessary, at |
23 | that it will not switch between coroutines unless necessary, at |
| 24 | easily-identified points in your program, so locking and parallel access |
24 | easily-identified points in your program, so locking and parallel access |
| 25 | are rarely an issue, making coroutine programming much safer than |
25 | are rarely an issue, making coroutine programming much safer than |
| 26 | threads programming. |
26 | threads programming. |
| 27 | |
27 | |
| … | |
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| 41 | $current (or as function: current) |
41 | $current (or as function: current) |
| 42 | The current coroutine (the last coroutine switched to). The initial |
42 | The current coroutine (the last coroutine switched to). The initial |
| 43 | value is $main (of course). |
43 | value is $main (of course). |
| 44 | |
44 | |
| 45 | This variable is strictly *read-only*. It is provided for |
45 | This variable is strictly *read-only*. It is provided for |
| 46 | performance reasons. If performance is not essentiel you are |
46 | performance reasons. If performance is not essential you are |
| 47 | encouraged to use the "Coro::current" function instead. |
47 | encouraged to use the "Coro::current" function instead. |
| 48 | |
48 | |
| 49 | $idle |
49 | $idle |
| 50 | A callback that is called whenever the scheduler finds no ready |
50 | A callback that is called whenever the scheduler finds no ready |
| 51 | coroutines to run. The default implementation prints "FATAL: |
51 | coroutines to run. The default implementation prints "FATAL: |
| … | |
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| 66 | async { ... } [@args...] |
66 | async { ... } [@args...] |
| 67 | Create a new asynchronous coroutine and return it's coroutine object |
67 | Create a new asynchronous coroutine and return it's coroutine object |
| 68 | (usually unused). When the sub returns the new coroutine is |
68 | (usually unused). When the sub returns the new coroutine is |
| 69 | automatically terminated. |
69 | automatically terminated. |
| 70 | |
70 | |
| 71 | Calling "exit" in a coroutine will not work correctly, so do not do |
71 | Calling "exit" in a coroutine will do the same as calling exit |
| 72 | that. |
72 | outside the coroutine. Likewise, when the coroutine dies, the |
| 73 | |
73 | program will exit, just as it would in the main program. |
| 74 | When the coroutine dies, the program will exit, just as in the main |
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| 75 | program. |
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| 76 | |
74 | |
| 77 | # create a new coroutine that just prints its arguments |
75 | # create a new coroutine that just prints its arguments |
| 78 | async { |
76 | async { |
| 79 | print "@_\n"; |
77 | print "@_\n"; |
| 80 | } 1,2,3,4; |
78 | } 1,2,3,4; |
| … | |
… | |
| 99 | coros as required. |
97 | coros as required. |
| 100 | |
98 | |
| 101 | If you are concerned about pooled coroutines growing a lot because a |
99 | If you are concerned about pooled coroutines growing a lot because a |
| 102 | single "async_pool" used a lot of stackspace you can e.g. |
100 | single "async_pool" used a lot of stackspace you can e.g. |
| 103 | "async_pool { terminate }" once per second or so to slowly replenish |
101 | "async_pool { terminate }" once per second or so to slowly replenish |
| 104 | the pool. |
102 | the pool. In addition to that, when the stacks used by a handler |
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103 | grows larger than 16kb (adjustable with $Coro::POOL_RSS) it will |
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104 | also exit. |
| 105 | |
105 | |
| 106 | schedule |
106 | schedule |
| 107 | Calls the scheduler. Please note that the current coroutine will not |
107 | Calls the scheduler. Please note that the current coroutine will not |
| 108 | be put into the ready queue, so calling this function usually means |
108 | be put into the ready queue, so calling this function usually means |
| 109 | you will never be called again unless something else (e.g. an event |
109 | you will never be called again unless something else (e.g. an event |
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| 120 | # wake up sleeping coroutine |
120 | # wake up sleeping coroutine |
| 121 | $current->ready; |
121 | $current->ready; |
| 122 | undef $current; |
122 | undef $current; |
| 123 | }; |
123 | }; |
| 124 | |
124 | |
| 125 | # call schedule until event occured. |
125 | # call schedule until event occurred. |
| 126 | # in case we are woken up for other reasons |
126 | # in case we are woken up for other reasons |
| 127 | # (current still defined), loop. |
127 | # (current still defined), loop. |
| 128 | Coro::schedule while $current; |
128 | Coro::schedule while $current; |
| 129 | } |
129 | } |
| 130 | |
130 | |
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| 155 | Create a new coroutine and return it. When the sub returns the |
155 | Create a new coroutine and return it. When the sub returns the |
| 156 | coroutine automatically terminates as if "terminate" with the |
156 | coroutine automatically terminates as if "terminate" with the |
| 157 | returned values were called. To make the coroutine run you must |
157 | returned values were called. To make the coroutine run you must |
| 158 | first put it into the ready queue by calling the ready method. |
158 | first put it into the ready queue by calling the ready method. |
| 159 | |
159 | |
| 160 | Calling "exit" in a coroutine will not work correctly, so do not do |
160 | See "async" for additional discussion. |
| 161 | that. |
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| 162 | |
161 | |
| 163 | $success = $coroutine->ready |
162 | $success = $coroutine->ready |
| 164 | Put the given coroutine into the ready queue (according to it's |
163 | Put the given coroutine into the ready queue (according to it's |
| 165 | priority) and return true. If the coroutine is already in the ready |
164 | priority) and return true. If the coroutine is already in the ready |
| 166 | queue, do nothing and return false. |
165 | queue, do nothing and return false. |
| … | |
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| 215 | with a coroutine. |
214 | with a coroutine. |
| 216 | |
215 | |
| 217 | GLOBAL FUNCTIONS |
216 | GLOBAL FUNCTIONS |
| 218 | Coro::nready |
217 | Coro::nready |
| 219 | Returns the number of coroutines that are currently in the ready |
218 | Returns the number of coroutines that are currently in the ready |
| 220 | state, i.e. that can be swicthed to. The value 0 means that the only |
219 | state, i.e. that can be switched to. The value 0 means that the only |
| 221 | runnable coroutine is the currently running one, so "cede" would |
220 | runnable coroutine is the currently running one, so "cede" would |
| 222 | have no effect, and "schedule" would cause a deadlock unless there |
221 | have no effect, and "schedule" would cause a deadlock unless there |
| 223 | is an idle handler that wakes up some coroutines. |
222 | is an idle handler that wakes up some coroutines. |
| 224 | |
223 | |
| 225 | my $guard = Coro::guard { ... } |
224 | my $guard = Coro::guard { ... } |
| 226 | This creates and returns a guard object. Nothing happens until the |
225 | This creates and returns a guard object. Nothing happens until the |
| 227 | objetc gets destroyed, in which case the codeblock given as argument |
226 | object gets destroyed, in which case the codeblock given as argument |
| 228 | will be executed. This is useful to free locks or other resources in |
227 | will be executed. This is useful to free locks or other resources in |
| 229 | case of a runtime error or when the coroutine gets canceled, as in |
228 | case of a runtime error or when the coroutine gets canceled, as in |
| 230 | both cases the guard block will be executed. The guard object |
229 | both cases the guard block will be executed. The guard object |
| 231 | supports only one method, "->cancel", which will keep the codeblock |
230 | supports only one method, "->cancel", which will keep the codeblock |
| 232 | from being executed. |
231 | from being executed. |
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| 246 | it, returning the new coderef. This means that the new coderef will |
245 | it, returning the new coderef. This means that the new coderef will |
| 247 | return immediately without blocking, returning nothing, while the |
246 | return immediately without blocking, returning nothing, while the |
| 248 | original code ref will be called (with parameters) from within its |
247 | original code ref will be called (with parameters) from within its |
| 249 | own coroutine. |
248 | own coroutine. |
| 250 | |
249 | |
| 251 | The reason this fucntion exists is that many event libraries (such |
250 | The reason this function exists is that many event libraries (such |
| 252 | as the venerable Event module) are not coroutine-safe (a weaker form |
251 | as the venerable Event module) are not coroutine-safe (a weaker form |
| 253 | of thread-safety). This means you must not block within event |
252 | of thread-safety). This means you must not block within event |
| 254 | callbacks, otherwise you might suffer from crashes or worse. |
253 | callbacks, otherwise you might suffer from crashes or worse. |
| 255 | |
254 | |
| 256 | This function allows your callbacks to block by executing them in |
255 | This function allows your callbacks to block by executing them in |
| … | |
… | |
| 264 | BUGS/LIMITATIONS |
263 | BUGS/LIMITATIONS |
| 265 | - you must make very sure that no coro is still active on global |
264 | - you must make very sure that no coro is still active on global |
| 266 | destruction. very bad things might happen otherwise (usually segfaults). |
265 | destruction. very bad things might happen otherwise (usually segfaults). |
| 267 | |
266 | |
| 268 | - this module is not thread-safe. You should only ever use this module |
267 | - this module is not thread-safe. You should only ever use this module |
| 269 | from the same thread (this requirement might be losened in the future |
268 | from the same thread (this requirement might be loosened in the future |
| 270 | to allow per-thread schedulers, but Coro::State does not yet allow |
269 | to allow per-thread schedulers, but Coro::State does not yet allow |
| 271 | this). |
270 | this). |
| 272 | |
271 | |
| 273 | SEE ALSO |
272 | SEE ALSO |
| 274 | Support/Utility: Coro::Cont, Coro::Specific, Coro::State, Coro::Util. |
273 | Support/Utility: Coro::Cont, Coro::Specific, Coro::State, Coro::Util. |
