This is a sweet spot of thread functionality for me at the moment, mixing boost and c++11, so I’m throwing it down here.\u00a0 It’s also in my Reusable code on git.<\/p>\n
\/\/ --------------------------------------------------------------------\r\n\/\/ CONCISE EXAMPLE OF THREAD WITH EXTERNALLY-ACCESSIBLE STATUS AND DATA\r\n\/\/ --------------------------------------------------------------------\r\n\/\/ We create a vector, and create a thread to start stuffing it.\r\n\/\/ Externally, we can check the status of the job, and have mutex access to the data.\r\n\/\/ The atomic job stage is SO CHEAP to change and check, do it all day long as needed.\r\n\/\/ Initially, externally, we check the job stage.\r\n\/\/ Meanwhile, we do a bunch of intense work inside the mutex.\r\n\/\/ Then we do smaller work with frequent mutexing, allowing interruption.\r\n\/\/ Great patterns, use them brother!\r\n\/\/ Hells to the yeah.\r\n\/\/ --------------------------------------------------------------------\r\nstd::atomic<int32_t> job_stage(0);\r\nstd::unordered_set<int> data;\r\nboost::shared_mutex data_guard;\r\ndata.insert(-1);\r\nstd::thread t([&job_stage,&data,&data_guard] {\r\n \/\/ stage 1 = jam in data\r\n job_stage = 1;\r\n {\r\n boost::upgrade_lock<boost::shared_mutex> lock(data_guard);\r\n boost::upgrade_to_unique_lock<boost::shared_mutex> uniqueLock(lock);\r\n for (int loop = 0; loop < 2000; ++loop)\r\n {\r\n std::this_thread::sleep_for(1ms);\r\n data.insert(loop);\r\n }\r\n }\r\n \/\/ stage 2 = mutex-jam data, allowing intervention\r\n job_stage = 2;\r\n for (int loop = 3000000; loop < 4000000 && job_stage == 2; ++loop)\r\n {\r\n boost::upgrade_lock<boost::shared_mutex> lock(data_guard);\r\n boost::upgrade_to_unique_lock<boost::shared_mutex> uniqueLock(lock);\r\n data.insert(loop);\r\n }\r\n cout << \"thread exiting...\" << endl;\r\n});\r\n\r\ncout << \"pre mutex job stage: \" << job_stage << endl;\r\n\r\nfor (int check = 0; check < 5; ++check)\r\n{\r\n std::this_thread::sleep_for(200ms);\r\n \/\/ not sure why i was getting std::hex output...\r\n cout << \"check \" << check << \" job stage: \";\r\n {\r\n boost::upgrade_lock<boost::shared_mutex> lock(data_guard);\r\n cout << dec << job_stage << \" data size \" << data.size();\r\n }\r\n cout << endl;\r\n}\r\n\r\n\/\/ We can trigger the thread to exit.\r\njob_stage = 3;\r\n\r\n\/\/ Let's see what happens if we don't join until after the thread is done.\r\nstd::this_thread::sleep_for(300ms);\r\ncout << \"done sleeping\" << endl;\r\n\r\n\/\/ NOW we will block to ensure the thread finishes.\r\ncout << \"joining\" << endl;\r\nt.join();\r\ncout << \"all done\" << endl;\r\n\/\/ --------------------------------------------------------------------<\/pre>\nOutput:<\/p>\n
pre mutex job stage: 1
\ncheck 0 job stage: 2 data size 2031
\ncheck 1 job stage: 2 data size 225848
\ncheck 2 job stage: 2 data size 456199
\ncheck 3 job stage: 2 data size 726576
\ncheck 4 job stage: 2 data size 936429
\nthread exiting...
\ncheck 5 job stage: 2 data size 1002001
\ndone sleeping
\njoining
\nall done<\/code><\/p>\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"This is a sweet spot of thread functionality for me at the moment, mixing boost and c++11, so I’m throwing it down here.\u00a0 It’s also in my Reusable code on git. \/\/ ——————————————————————– \/\/ CONCISE EXAMPLE OF THREAD WITH EXTERNALLY-ACCESSIBLE STATUS AND DATA \/\/ ——————————————————————– \/\/ We create a vector, and create a thread to […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[22,19],"tags":[],"class_list":["post-2182","post","type-post","status-publish","format-standard","hentry","category-cpp","category-opensource"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t