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Win32 线程的创建&信号量临界资源&事件对象
背景:
写了个程序,主要实现的功能为主线程创建两个子线程,之后主线程进入等待事件的循环。子线程1对临界资源cnt的值减2并输出cnt的值。子线程2对cnt的值加1并输出cnt的值,且当cnt为50的时候触发事件对象hend_even,子进程2退出。主线程收到hend_even后杀死子线程1,之后进入scanf阻塞。。。
代码示例:
#include <windows.h> #include <stdio.h> DWORD WINAPI funAproc(LPVOID lpParameter); DWORD WINAPI funBproc(LPVOID lpParameter); int cnt=100; //共享数据 HANDLE hmutex_cnt; //cnt的信号量锁 HANDLE hend_even; //事件 void main() { HANDLE th1,th2; //false表示当前主线程不拥有该信号,true表示创建该信号后备主线程拥有 hmutex_cnt = CreateMutex(NULL,FALSE,NULL); //第二个参数: //true(人工重置事件对象,等待该事件的所有进程都将进入运行 //false(自动重置事件对象),等待该事件中的一个进程可变为调度 //第三个参数: //true: 创建该事件对象后,触发事件,false:不触发事件。 hend_even = CreateEvent(NULL,TRUE,FALSE,NULL); int x=2;//带参线程 //funAproc为线程入口,&x为线程函数参数,该参数为(void*)类型,如果多余一个参数可以采用传递结构体的方式 th1 = CreateThread(NULL,0,funAproc,&x,0,NULL); th2 = CreateThread(NULL,0,funBproc,NULL,0,NULL); while (TRUE) { if (cnt == 0) break; //Sleep(1); if(WAIT_OBJECT_0 == WaitForSingleObject(hend_even,100)){//主线程等待th2发出“终止th1的事件”,即hend_even TerminateThread(th1,1); //终止线程 break; } } printf("back to main thread... \n "); int i; while (scanf("%d",&i)) { ; } } DWORD WINAPI funAproc(LPVOID lpParameter){ int b,c; int k = *(int*)lpParameter; while (cnt>0) { WaitForSingleObject(hmutex_cnt,INFINITE);//获取信号量,对临界资源(cnt)进行W操作 cnt -= k; printf("thread A delete 2 of cnt = %d\n",cnt); ReleaseMutex(hmutex_cnt); //释放信号量 } return 0; } DWORD WINAPI funBproc(LPVOID lpParameter){ while (cnt>0) { WaitForSingleObject(hmutex_cnt,INFINITE);//获取信号量,对临界资源(cnt)进行W操作 cnt = cnt + 1; printf("thread B add 1 of cnt = %d\n",cnt); if (cnt == 50) //当cnt == 50的时候,终止th1和th2,此时th2触发hend_even事件,并退出 { SetEvent(hend_even); printf("proc B stop to sail ticket...\n"); ReleaseMutex(hmutex_cnt); //释放信号量 exit(0); } ReleaseMutex(hmutex_cnt); //释放信号量 } return 0; }
运行结果:
thread A delete 2 of cnt = 98
thread B add 1 of cnt = 99
thread A delete 2 of cnt = 97
thread B add 1 of cnt = 98
thread A delete 2 of cnt = 96
thread B add 1 of cnt = 97
thread A delete 2 of cnt = 95
thread B add 1 of cnt = 96
thread A delete 2 of cnt = 94
thread B add 1 of cnt = 95
thread A delete 2 of cnt = 93
thread B add 1 of cnt = 94
thread A delete 2 of cnt = 92
thread B add 1 of cnt = 93
thread A delete 2 of cnt = 91
thread B add 1 of cnt = 92
thread A delete 2 of cnt = 90
thread B add 1 of cnt = 91
thread A delete 2 of cnt = 89
thread B add 1 of cnt = 90
thread A delete 2 of cnt = 88
thread B add 1 of cnt = 89
...
thread A delete 2 of cnt = 51
thread B add 1 of cnt = 52
thread A delete 2 of cnt = 50
thread B add 1 of cnt = 51
thread A delete 2 of cnt = 49
thread B add 1 of cnt = 50
proc B stop to sail ticket...
proc B stop to sail ticket...
back to main thread...
参考:
http://www.cnblogs.com/1314NNNKKK/p/3386375.html
http://hi.baidu.com/kdlipm/item/005be8eb29d785e1fa42bae5
Win32 线程的创建&信号量临界资源&事件对象