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34 | applicability. |
34 | applicability. |
35 | |
35 | |
36 | The newest version of this document can be found at |
36 | The newest version of this document can be found at |
37 | L<http://pod.tst.eu/http://cvs.schmorp.de/Coro-Multicore/perlmulticore.h>. |
37 | L<http://pod.tst.eu/http://cvs.schmorp.de/Coro-Multicore/perlmulticore.h>. |
38 | |
38 | |
39 | The nwest version of the header fgile itself, which |
39 | The newest version of the header file itself, which |
40 | includes this documentation, can be downloaded from |
40 | includes this documentation, can be downloaded from |
41 | L<http://cvs.schmorp.de/Coro-Multicore/perlmulticore.h>. |
41 | L<http://cvs.schmorp.de/Coro-Multicore/perlmulticore.h>. |
42 | |
42 | |
43 | =head1 HOW DO I USE THIS IN MY MODULES? |
43 | =head1 HOW DO I USE THIS IN MY MODULES? |
44 | |
44 | |
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118 | if (res) |
118 | if (res) |
119 | { |
119 | { |
120 | // error, assume lock is held by another process and do it the slow way |
120 | // error, assume lock is held by another process and do it the slow way |
121 | perlinterp_release (); |
121 | perlinterp_release (); |
122 | res = fcntl (fd, F_SETLKW, &flock); |
122 | res = fcntl (fd, F_SETLKW, &flock); |
123 | perlinterp_release (); |
123 | perlinterp_acquire (); |
124 | } |
124 | } |
125 | |
125 | |
126 | =head1 THE HARD AND FAST RULES |
126 | =head1 THE HARD AND FAST RULES |
127 | |
127 | |
128 | As with everything, there are a number of rules to follow. |
128 | As with everything, there are a number of rules to follow. |
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198 | pthread_mutex_lock (&my_mutex); |
198 | pthread_mutex_lock (&my_mutex); |
199 | do_your_non_thread_safe_thing (); |
199 | do_your_non_thread_safe_thing (); |
200 | pthread_mutex_unlock (&my_mutex); |
200 | pthread_mutex_unlock (&my_mutex); |
201 | perlinterp_acquire (); |
201 | perlinterp_acquire (); |
202 | |
202 | |
203 | This isn't as trivial as it looks though, as you need to find out which |
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204 | threading system is in use (with L<Coro::Multicore>, it currently is |
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205 | always pthreads). |
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206 | |
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207 | =item I<Don't> get confused by having to release first. |
203 | =item I<Don't> get confused by having to release first. |
208 | |
204 | |
209 | In many real world scenarios, you acquire a resource, do something, then |
205 | In many real world scenarios, you acquire a resource, do something, then |
210 | release it again. Don't let this confuse you, with this, you already own |
206 | release it again. Don't let this confuse you, with this, you already own |
211 | the resource (the perl interpreter) so you have to I<release> first, and |
207 | the resource (the perl interpreter) so you have to I<release> first, and |
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304 | efficient when not needed, low code and data size overhead and broad |
300 | efficient when not needed, low code and data size overhead and broad |
305 | applicability. |
301 | applicability. |
306 | |
302 | |
307 | =back |
303 | =back |
308 | |
304 | |
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305 | |
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306 | =head1 DISABLING PERL MULTICORE AT COMPILE TIME |
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307 | |
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308 | You can disable the complete perl multicore API by defining the |
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309 | symbol C<PERL_MULTICORE_DISABLE> to C<1> (e.g. by specifying |
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310 | F<-DPERL_MULTICORE_DISABLE> as compiler argument). |
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311 | |
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312 | This will leave no traces of the API in the compiled code, suitable |
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313 | "empty" C<perl_release> and C<perl_acquire> definitions will be provided. |
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314 | |
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315 | This could be added to perl's C<CPPFLAGS> when configuring perl on |
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316 | platforms that do not support threading at all for example. |
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317 | |
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318 | |
309 | =head1 AUTHOR |
319 | =head1 AUTHOR |
310 | |
320 | |
311 | Marc A. Lehmann <perlmulticore@schmorp.de> |
321 | Marc A. Lehmann <perlmulticore@schmorp.de> |
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322 | http://perlmulticore.schmorp.de/ |
312 | |
323 | |
313 | =head1 LICENSE |
324 | =head1 LICENSE |
314 | |
325 | |
315 | The F<perlmulticore.h> is put into the public domain. Where this is legally |
326 | The F<perlmulticore.h> header file is put into the public |
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327 | domain. Where this is legally not possible, or at your |
316 | not possible, or at your option, it can be licensed under creativecommons |
328 | option, it can be licensed under creativecommons CC0 |
317 | CC0 license: L<https://creativecommons.org/publicdomain/zero/1.0/>. |
329 | license: L<https://creativecommons.org/publicdomain/zero/1.0/>. |
318 | |
330 | |
319 | =cut |
331 | =cut |
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332 | |
320 | */ |
333 | */ |
321 | |
334 | |
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335 | #define PERL_MULTICORE_MAJOR 1 /* bumped on incompatible changes */ |
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336 | #define PERL_MULTICORE_MINOR 0 /* bumped on every change */ |
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337 | |
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338 | #if PERL_MULTICORE_DISABLE |
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339 | |
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340 | #define perlinterp_release() do { } while (0) |
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341 | #define perlinterp_acquire() do { } while (0) |
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342 | |
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343 | #else |
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344 | |
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345 | /* this struct is shared between all modules, and currently */ |
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346 | /* contain only the two function pointers for release/acquire */ |
322 | struct perl_multicore_api |
347 | struct perl_multicore_api |
323 | { |
348 | { |
324 | void (*pmapi_release)(void); |
349 | void (*pmapi_release)(void); |
325 | void (*pmapi_acquire)(void); |
350 | void (*pmapi_acquire)(void); |
326 | }; |
351 | }; |
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333 | = (struct perl_multicore_api *)&perl_multicore_api_init; |
358 | = (struct perl_multicore_api *)&perl_multicore_api_init; |
334 | |
359 | |
335 | #define perlinterp_release() perl_multicore_api->pmapi_release () |
360 | #define perlinterp_release() perl_multicore_api->pmapi_release () |
336 | #define perlinterp_acquire() perl_multicore_api->pmapi_acquire () |
361 | #define perlinterp_acquire() perl_multicore_api->pmapi_acquire () |
337 | |
362 | |
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363 | /* this is the release/acquire implementation used as fallback */ |
338 | static void |
364 | static void |
339 | perl_multicore_nop (void) |
365 | perl_multicore_nop (void) |
340 | { |
366 | { |
341 | } |
367 | } |
342 | |
368 | |
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369 | /* this is the initial implementation of "release" - it initialises */ |
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370 | /* the api and then calls the real release function */ |
343 | static void |
371 | static void |
344 | perl_multicore_init (void) |
372 | perl_multicore_init (void) |
345 | { |
373 | { |
346 | dTHX; |
374 | dTHX; |
347 | |
375 | |
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365 | /* call the real (or dummy) implementation now */ |
393 | /* call the real (or dummy) implementation now */ |
366 | perlinterp_release (); |
394 | perlinterp_release (); |
367 | } |
395 | } |
368 | |
396 | |
369 | #endif |
397 | #endif |
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398 | |
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399 | #endif |