黑馬《linux系統程式設計》學習筆記（從76到80）
阿新 • • 發佈：2019-01-01
七十六. 執行緒同步的思想
七十七. 互斥鎖相關的函式
七十八. 使用互斥鎖，實現執行緒同步
首先是 pthread_mutex.c
#include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <string.h> #include <pthread.h> #define MAX 10000 // 全域性變數 int number; //建立一把互斥鎖 pthread_mutex_t mutex; // 執行緒處理函式 void* funcA_num(void* arg) { for(int i=0; i<MAX; ++i) { //訪問全域性變數之前加鎖 //如果mutex被鎖上了，程式碼阻塞在當前位置 pthread_mutex_lock(&mutex); int cur = number; cur++; number = cur; printf("Thread A, id = %lu, number = %d\n", pthread_self(), number); //解鎖 pthread_mutex_unlock(&mutex); usleep(10); } return NULL; } void* funcB_num(void* arg) { for(int i=0; i<MAX; ++i) { pthread_mutex_lock(&mutex); int cur = number; cur++; number = cur; printf("Thread B, id = %lu, number = %d\n", pthread_self(), number); pthread_mutex_unlock(&mutex); usleep(10); } return NULL; } int main(int argc, const char* argv[]) { pthread_t p1, p2; //初始化互斥鎖 pthread_mutex_init(&mutex,NULL); // 建立兩個子執行緒 pthread_create(&p1, NULL, funcA_num, NULL); pthread_create(&p2, NULL, funcB_num, NULL); // 阻塞，資源回收 pthread_join(p1, NULL); pthread_join(p2, NULL); //釋放互斥鎖資源 pthread_mutex_destroy(&mutex); return 0; }
執行一下
[[email protected]_0_15_centos 8Day]# vim pthread_mutex_.c [[email protected]_0_15_centos 8Day]# gcc pthread_mutex_.c -o p_m -std=gnu99 -lpthread [[email protected]_0_15_centos 8Day]# ls a.out p_e process_r.c pthread_create.c pthread_mutex_.c deamon.c p_j process_work.c pthread_exit.c pthread_uncle.c loop_pthread_create.c p_m pthread_attr.c pthread_join.c setsid.c [[email protected]_0_15_centos 8Day]# ./p_m Thread A, id = 140197652313856, number = 1 Thread B, id = 140197643921152, number = 2 Thread A, id = 140197652313856, number = 3 Thread B, id = 140197643921152, number = 4 Thread A, id = 140197652313856, number = 5 Thread A, id = 140197652313856, number = 6 Thread B, id = 140197643921152, number = 7 Thread A, id = 140197652313856, number = 8 Thread B, id = 140197643921152, number = 9 Thread B, id = 140197643921152, number = 10 Thread A, id = 140197652313856, number = 11 Thread B, id = 140197643921152, number = 12 Thread A, id = 140197652313856, number = 13 Thread A, id = 140197652313856, number = 14 …………………… …………………… Thread A, id = 140197652313856, number = 1696 Thread B, id = 140197643921152, number = 1697 Thread B, id = 140197643921152, number = 1698 Thread A, id = 140197652313856, number = 1699 Thread B, id = 140197643921152, number = 1700 Thread A, id = 140197652313856, number = 1701 Thread A, id = 140197652313856, number = 1702 Thread B, id = 140197643921152, number = 1703 Thread A, id = 140197652313856, number = 1704 Thread B, id = 140197643921152, number = 1705 Thread B, id = 140197643921152, number = 1706 Thread A, id = 140197652313856, number = 1707 Thread B, id = 140197643921152, number = 1708 Thread A, id = 140197652313856, number = 1709 Thread A, id = 140197652313856, number = 1710 Thread B, id = 140197643921152, number = 1711 Thread A, id = 140197652313856, number = 1712 Thread B, id = 140197643921152, number = 1713 Thread B, id = 140197643921152, number = 1714 Thread A, id = 140197652313856, number = 1715 Thread B, id = 140197643921152, number = 1716 Thread A, id = 140197652313856, number = 1717 Thread A, id = 140197652313856, number = 1718 Thread B, id = 140197643921152, number = 1719 Thread A, id = 140197652313856, number = 1720 Thread B, id = 140197643921152, number = 1721 Thread B, id = 140197643921152, number = 1722 Thread A, id = 140197652313856, number = 1723 Thread B, id = 140197643921152, number = 1724 Thread A, id = 140197652313856, number = 1725 Thread B, id = 140197643921152, number = 1726 Thread A, id = 140197652313856, number = 1727 Thread A, id = 140197652313856, number = 1728 Thread B, id = 140197643921152, number = 1729 Thread A, id = 140197652313856, number = 1730 Thread B, id = 140197643921152, number = 1731
七十九. 學習目標
八十. 互斥鎖使用的時候需要注意的問題
