\u5b9a\u4e49：\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bfb\u5199\u540c\u4e00\u4efd\u5171\u4eab\u6570\u636e，\u6ca1\u6709\u52a0\u4efb\u4f55\u4fdd\u62a4，\u6700\u7ec8\u8ba1\u7b97\u7ed3\u679c\u9519\u4e71\u3002<\/p>\n
\u539f\u7406：\u4e00\u6761\u53d8\u91cf\u81ea\u589ecnt++\u5728CPU\u4e0d\u662f\u4e00\u6761\u6307\u4ee4，\u4f1a\u62c6\u5206\u6210\u4e09\u6b65：\u8bfb->\u4fee\u6539->\u5199\u56de\u3002<\/p>\n
\u4e24\u4e2a\u7ebf\u7a0b\u5e76\u53d1\u6267\u884c，\u6b65\u9aa4\u7a7f\u63d2\u6253\u4e71，\u5c31\u4f1a\u51fa\u73b0\u6570\u636e\u9519\u8bef\u3002<\/p>\n
\u4f8b\u5b50：cnt\u521d\u59cb=0，\u4e24\u4e2a\u7ebf\u7a0b\u90fd\u6267\u884ccnt++，\u9884\u671f\u53d8\u62102，\u5b9e\u9645\u53ef\u80fd\u7ed3\u679c\u4e3a1\u3002<\/p>\n
\u89e3\u51b3\u65b9\u5f0f：\u4e92\u65a5\u9501mutex，\u539f\u5b50\u9501atomic\u3002<\/p>\n<\/p>\n
C++11\u7ebf\u7a0b\u7c7b，\u7528\u6765\u521b\u5efa\u5e76\u542f\u52a8\u5b50\u7ebf\u7a0b，\u6267\u884c\u4efb\u52a1\u3002<\/p>\n
\u00a0 t.join()：\u4e3b\u7ebf\u7a0b\u963b\u585e\u7b49\u5f85\u5b50\u7ebf\u7a0b\u6267\u884c\u5b8c\u6bd5，\u56de\u6536\u7ebf\u7a0b\u8d44\u6e90；\u4e3b\u7ebf\u7a0b\u4e0d\u7b49\u5b8c\u4e0d\u80fd\u5f80\u4e0b\u8d70；<\/p>\n
\u00a0 t.detach()：\u5206\u79bb\u7ebf\u7a0b，\u5b50\u7ebf\u7a0b\u540e\u53f0\u72ec\u7acb\u8dd1，\u4e3b\u7ebf\u7a0b\u4e0d\u7528\u7b49\u5f85；\u98ce\u9669：\u4e3b\u7ebf\u7a0b\u9000\u51fa，\u5b50\u7ebf\u7a0b\u76f4\u63a5\u88ab\u6740\u6b7b\u3002<\/p>\n
#include <iostream>
\n#include <thread>
\nusing namespace std;<\/p>\n
void task()
\n{
\n cout << "\u5b50\u7ebf\u7a0b\u8fd0\u884c" << endl;
\n}<\/p>\n
int main()
\n{
\n thread t(task); \/\/ \u521b\u5efa\u7ebf\u7a0b，\u7acb\u523b\u542f\u52a8
\n t.join(); \/\/ \u7b49\u5f85\u5b50\u7ebf\u7a0b\u7ed3\u675f
\n cout << "\u4e3b\u7ebf\u7a0b\u7ed3\u675f" << endl;
\n return 0;
\n}<\/p>\n
\u4f5c\u7528：\u4fdd\u62a4\u5171\u4eab\u8d44\u6e90，\u540c\u4e00\u65f6\u523b\u53ea\u5141\u8bb8\u4e00\u4e2a\u7ebf\u7a0b\u62ff\u5230\u9501，\u8bbf\u95ee\u4e34\u754c\u533a\u4ee3\u7801，\u907f\u514d\u7ade\u6001\u6761\u4ef6\u3002<\/p>\n
\u00a0 lock()：\u5c1d\u8bd5\u83b7\u53d6\u9501；\u9501\u88ab\u5360\u7528\u65f6，\u5f53\u524d\u7ebf\u7a0b\u963b\u585e\u4f11\u7720，\u7b49\u522b\u4eba\u91ca\u653e\u3002<\/p>\n
\u00a0 unlock()：\u91ca\u653e\u9501，\u5176\u4ed6\u7b49\u5f85\u7ebf\u7a0b\u53ef\u4ee5\u67aa\u9501\u3002<\/p>\n
\u7f3a\u70b9：\u624b\u52a8lock，unlock\u5f88\u5371\u9669\u3002\u5982\u679c\u4e2d\u95f4\u4ee3\u7801return\u6216\u8005\u629b\u51fa\u5f02\u5e38，unlock\u6ca1\u6709\u673a\u4f1a\u6267\u884c->\u6b7b\u9501\u3002<\/p>\n
#include <iostream>
\n#include <thread>
\n#include <mutex>
\nusing namespace std;<\/p>\n
mutex mtx;
\nint cnt = 0;<\/p>\n
void add()
\n{
\n mtx.lock(); \/\/ \u624b\u52a8\u4e0a\u9501
\n cnt++; \/\/ \u4e34\u754c\u533a，\u540c\u4e00\u65f6\u95f4\u53ea\u80fd\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884c
\n mtx.unlock(); \/\/ \u624b\u52a8\u89e3\u9501
\n}<\/p>\n
int main()
\n{
\n thread t1(add);
\n thread t2(add);
\n t1.join();
\n t2.join();
\n cout << cnt << endl;
\n return 0;
\n}<\/p>\n
\u98ce\u9669\u6f14\u793a（\u4f1a\u9020\u6210\u6b7b\u9501）<\/p>\n
void add()
\n{
\n mtx.lock();
\n cnt++;
\n if (cnt > 0)
\n return; \/\/ \u51fd\u6570\u76f4\u63a5return，\u4e0b\u9762unlock\u6267\u884c\u4e0d\u5230！
\n mtx.unlock();
\n}<\/p>\n
\u4e00\u65e6return\u6216\u8005\u629b\u51fa\u5f02\u5e38，unlock\u4e0d\u4f1a\u6267\u884c，\u9501\u6c38\u4e45\u5360\u7528->\u6b7b\u9501\u3002<\/p>\n<\/p>\n
RAII\u601d\u8def：\u6784\u9020\u51fd\u6570\u4e0a\u9501，\u6790\u6784\u51fd\u6570\u81ea\u52a8\u89e3\u9501\u3002<\/p>\n
\u521b\u5efalock_guard\u5bf9\u8c61\u81ea\u52a8lock()；\u5bf9\u8c61\u79bb\u5f00\u4f5c\u7528\u57df（\u82b1\u62ec\u53f7\u7ed3\u675f，return，\u5f02\u5e38），\u81ea\u52a8\u6790\u6784\u8c03\u7528unlock()\u3002<\/p>\n
\u4e0d\u9700\u8981\u624b\u52a8\u5199unlock，\u907f\u514d\u5fd8\u8bb0\u91ca\u653e\u9501\u9020\u6210\u6b7b\u9501，\u5de5\u7a0b\u4ee3\u7801\u9996\u9009\u3002<\/p>\n
#include <iostream>
\n#include <thread>
\n#include <mutex>
\nusing namespace std;<\/p>\n
mutex mtx;
\nint cnt = 0;<\/p>\n
void add()
\n{
\n \/\/ \u521b\u5efalg\u5bf9\u8c61，\u6784\u9020\u51fd\u6570\u81ea\u52a8lock()
\n lock_guard<mutex> lg(mtx);
\n cnt++;<\/p>\n
\/\/ \u5c31\u7b97\u8fd9\u91ccreturn \/ throw\u5f02\u5e38，lg\u51fa\u4f5c\u7528\u57df\u4f1a\u81ea\u52a8\u6790\u6784，\u8c03\u7528unlock
\n \/\/ \u79bb\u5f00{}，lg\u9500\u6bc1，\u81ea\u52a8\u89e3\u9501
\n}<\/p>\n
int main()
\n{
\n thread t1(add);
\n thread t2(add);
\n t1.join();
\n t2.join();
\n cout << cnt << endl;
\n return 0;
\n}<\/p>\n
\u539f\u7406：\u5bf9\u8c61\u751f\u547d\u5468\u671f\u7ed1\u5b9a\u4f5c\u7528\u57df，\u4e0d\u7528\u624b\u52a8\u5199unlock，\u89c4\u907f\u5fd8\u8bb0\u91ca\u653e\u9501\u7684\u95ee\u9898；<\/p>\n<\/p>\n
\u4f5c\u7528：\u7ebf\u7a0b\u7b49\u5f85，\u5524\u9192，\u907f\u514d\u5fd9\u7b49\u3002<\/p>\n
\u5fc5\u987b\u914d\u5408mutex\u4e00\u8d77\u4f7f\u7528\u3002<\/p>\n
\u00a0 wait(mutex)：\u91ca\u653e\u9501，\u7ebf\u7a0b\u4f11\u7720\u7b49\u5f85；\u88ab\u5524\u9192\u540e；\u91cd\u65b0\u62a2\u5360\u9501\u3002\u7ee7\u7eed\u6267\u884c\u3002<\/p>\n
\u00a0 \u00a0 \u00a0 wait<\/font>\u505a\u7684\u4e24\u4ef6\u5173\u952e\u4e8b： \u2460 \u8c03\u7528 wait \u7684\u65f6\u5019\u81ea\u52a8\u91ca\u653e mutex，\u522b\u7684\u7ebf\u7a0b（\u751f\u4ea7\u8005）\u624d\u6709\u673a\u4f1a\u62ff\u00a0 \u00a0 \u00a0 \u00a0 \u5230\u9501\u4fee\u6539\u6761\u4ef6； \u2461 \u6536\u5230 notify \u5524\u9192\u540e，\u91cd\u65b0\u62a2\u5360 mutex，\u62ff\u5230\u9501\u4e4b\u540e，\u518d\u53bb\u5224\u65ad\u6761\u4ef6\u3002<\/p>\n \u00a0 notify_one()：\u5524\u9192\u4e00\u4e2a\u6b63\u5728\u7b49\u5f85\u7684\u7ebf\u7a0b\u3002<\/p>\n \u00a0 notify_all()：\u5524\u9192\u5168\u90e8\u7b49\u5f85\u7684\u7ebf\u7a0b\u3002<\/p>\n \u7ecf\u5178\u573a\u666f：\u751f\u4ea7\u8005\u6d88\u8d39\u8005\u6a21\u578b<\/p>\n \u751f\u4ea7\u8005\u5f80\u961f\u5217\u653e\u6570\u636e；\u961f\u5217\u7a7a\u7684\u65f6\u5019，\u6d88\u8d39\u8005\u8c03\u7528wait()\u4f11\u7720，\u4e0d\u4e00\u76f4\u5faa\u73af\u8017CPU\u3002\u751f\u4ea7\u8005\u751f\u4ea7\u5b8c\u6570\u636e\u8c03\u7528notify，\u5524\u9192\u6d88\u8d39\u8005\u53d6\u6570\u636e\u3002<\/p>\n #include <iostream> mutex mtx; \/\/ \u751f\u4ea7\u8005：\u5f80\u961f\u5217\u653e\u6570\u636e \/\/ \u6d88\u8d39\u8005：\u4ece\u961f\u5217\u53d6\u6570\u636e int main() \u65e0\u9501，\u786c\u4ef6\u5c42\u9762\u4fdd\u8bc1\u64cd\u4f5c\u4e0d\u53ef\u62c6\u5206（\u539f\u5b50）<\/p>\n \u7b80\u5355\u53d8\u91cf\u8bfb\u5199，\u81ea\u589e\u4e0d\u7528mutex，\u4e0d\u4f1a\u4ea7\u751f\u7ade\u6001\u6761\u4ef6，\u6027\u80fd\u6bd4\u9501\u9ad8\u3002<\/p>\n \u5c40\u9650：\u53ea\u9002\u5408\u5355\u4e2a\u7b80\u5355\u53d8\u91cf\u64cd\u4f5c，\u590d\u6742\u4e1a\u52a1\u903b\u8f91，\u591a\u884c\u4ee3\u7801\u7684\u4e34\u754c\u533a，\u8fd8\u662f\u8981mutex\u3002<\/p>\n #include <iostream> atomic<int> cnt = 0; \/\/ \u539f\u5b50\u53d8\u91cf<\/p>\n void add() int main() \u4f18\u70b9：\u65e0\u9501，\u6027\u80fd\u9ad8\u4e8e mutex<\/p>\n \u5c40\u9650：\u53ea\u80fd\u5904\u7406\u5355\u4e2a\u53d8\u91cf\u7b80\u5355\u64cd\u4f5c\u3002 \u5982\u679c\u6709\u591a\u884c\u4ee3\u7801\u3001\u591a\u4e2a\u53d8\u91cf\u9700\u8981\u4fdd\u62a4，atomic \u5c31\u4e0d\u591f\u7528，\u5fc5\u987b mutex\u3002 \u4e3e\u4f8b：if(cnt >0) cnt–; \u8fd9\u4e24\u884c\u4e0d\u662f\u539f\u5b50\u7684，atomic \u65e0\u6cd5\u4fdd\u62a4\u3002<\/p>\n","protected":false},"excerpt":{"rendered":" \u4e00 \u7ade\u6001\u6761\u4ef6（\u7ade\u4e89\u6761\u4ef6）\u5b9a\u4e49：\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bfb\u5199\u540c\u4e00\u4efd\u5171\u4eab\u6570\u636e，\u6ca1\u6709\u52a0\u4efb\u4f55\u4fdd\u62a4，\u6700\u7ec8\u8ba1\u7b97\u7ed3\u679c\u9519\u4e71\u3002\u539f\u7406：\u4e00\u6761\u53d8\u91cf\u81ea\u589ecnt\u5728CPU\u4e0d\u662f\u4e00\u6761\u6307\u4ee4，\u4f1a\u62c6\u5206\u6210\u4e09\u6b65：\u8bfb->\u4fee\u6539->\u5199\u56de\u3002\u4e24\u4e2a\u7ebf\u7a0b\u5e76\u53d1\u6267\u884c，\u6b65\u9aa4\u7a7f\u63d2\u6253\u4e71，\u5c31\u4f1a\u51fa\u73b0\u6570\u636e\u9519\u8bef\u3002\u4f8b\u5b50：cnt\u521d\u59cb0，\u4e24\u4e2a\u7ebf\u7a0b\u90fd\u6267\u884ccnt，\u9884\u671f\u53d8\u62102，\u5b9e\u9645<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[55],"topic":[],"class_list":["post-115336","post","type-post","status-publish","format-standard","hentry","category-server","tag-c"],"yoast_head":"\n
\n#include <thread>
\n#include <mutex>
\n#include <condition_variable>
\n#include <queue>
\nusing namespace std;<\/p>\n
\ncondition_variable cv;
\nqueue<int> q;<\/p>\n
\nvoid producer()
\n{
\n for(int i = 1; i <= 3; i++)
\n {
\n unique_lock<mutex> lock(mtx);
\n q.push(i);
\n cout << "\u751f\u4ea7：" << i << endl;
\n cv.notify_one(); \/\/ \u5524\u91921\u4e2a\u7b49\u5f85\u7684\u6d88\u8d39\u8005
\n }
\n}<\/p>\n
\nvoid consumer()
\n{
\n while(true)
\n {
\n unique_lock<mutex> lock(mtx);
\n \/\/ \u961f\u5217\u7a7a，\u7b49\u5f85
\n cv.wait(lock, [&](){ return !q.empty(); });
\n int val = q.front();
\n q.pop();
\n cout << "\u6d88\u8d39：" << val << endl;
\n }
\n}<\/p>\n
\n{
\n thread t1(producer);
\n thread t2(consumer);
\n t1.join();
\n t2.detach();
\n return 0;
\n}<\/p>\n\u516d std::atomic\u539f\u5b50\u53d8\u91cf（\u65e0\u9501）<\/h2>\n
\n#include <thread>
\n#include <atomic>
\nusing namespace std;<\/p>\n
\n{
\n cnt++; \/\/ \u786c\u4ef6\u4fdd\u8bc1\u81ea\u589e\u662f\u539f\u5b50\u64cd\u4f5c，\u4e0d\u7528\u52a0\u9501，\u4e0d\u4f1a\u7ade\u6001
\n}<\/p>\n
\n{
\n thread t1(add);
\n thread t2(add);
\n t1.join();
\n t2.join();
\n cout << cnt << endl;
\n return 0;
\n}<\/p>\n