HANDLE CreateMutex(
LPSECURITY_ATTRIBUTES lpMutexAttributes,//
BOOL bInitialOwner, // flag for initial ownership
LPCTSTR lpName // pointer to mutex-object name
);
参数2:指示互斥对象的初始拥有者。 如果该值是真,调用者创建互斥对象,调用的线程获得互斥对象的所有权。 否则,不拥有所有权,此时互斥对象处于空闲状态,其他线程可以占用。
(-) 主线程中创建拥有所有权的互斥量,两个子线程中分别等待互斥量-》没有输出
1 DWORD WINAPI ThreadProc1(LPVOID lpParameter); 2 DWORD WINAPI ThreadProc2(LPVOID lpParameter); 3 4 int ticket = 50; 5 HANDLE hMutex = NULL; 6 7 int _tmain(int argc, _TCHAR* argv[]) 8 { 9 HANDLE handle1 = CreateThread(NULL,0,ThreadProc1,NULL,0,NULL); 10 HANDLE handle2 = CreateThread(NULL,0,ThreadProc2,NULL,0,NULL); 11 12 CloseHandle(handle1); 13 CloseHandle(handle2); 14 15 hMutex = CreateMutex(NULL,TRUE,NULL); //第二个参数为TRUE,互斥对象的所有权为主线程所有,非空闲状态 16 17 Sleep(4000); 18 19 return 0; 20 } 21 22 DWORD WINAPI ThreadProc1(LPVOID lpParameter) 23 { 24 25 //WaitForSingleObject(hMutex,INFINITE); //第二个参数为INFINITE表示一直等待,直到拥有互斥对象 26 while(TRUE) 27 { 28 29 WaitForSingleObject(hMutex,INFINITE); //第二个参数为INFINITE表示一直等待,直到拥有互斥对象 30 31 if ( ticket > 0 ) 32 { 33 Sleep(1); 34 35 printf("thread1 sale the ticket id is: %d ", ticket--); 36 } 37 else 38 { 39 break; 40 } 41 42 ReleaseMutex(hMutex); //使用完了,将互斥对象还给操作系统 43 } 44 //ReleaseMutex(hMutex); //使用完了,将互斥对象还给操作系统 45 return 0; 46 } 47 48 DWORD WINAPI ThreadProc2(LPVOID lpParameter) 49 { 50 51 while(TRUE) 52 { 53 54 WaitForSingleObject(hMutex,INFINITE); //第二个参数为INFINITE表示一直等待,直到拥有互斥对象 55 56 if ( ticket > 0 ) 57 { 58 59 Sleep(1); 60 61 printf("thread2 sale the ticket id is: %d ", ticket--); 62 63 } 64 else 65 { 66 break; 67 } 68 69 ReleaseMutex(hMutex); //使用完了,将互斥对象还给操作系统 70 } 71 72 return 0; 73 }
(二) 主线程中创建没有所有权的互斥量,两个子线程中分别等待互斥量-》输出如下
thread1 sale the ticket id is: 50
thread2 sale the ticket id is: 49
thread1 sale the ticket id is: 48
thread2 sale the ticket id is: 47
thread1 sale the ticket id is: 46
thread2 sale the ticket id is: 45
thread1 sale the ticket id is: 44
thread2 sale the ticket id is: 43
thread1 sale the ticket id is: 42
thread2 sale the ticket id is: 41
thread1 sale the ticket id is: 40
thread2 sale the ticket id is: 39
thread1 sale the ticket id is: 38
thread2 sale the ticket id is: 37
thread1 sale the ticket id is: 36
thread2 sale the ticket id is: 35
thread1 sale the ticket id is: 34
thread2 sale the ticket id is: 33
thread1 sale the ticket id is: 32
thread2 sale the ticket id is: 31
thread1 sale the ticket id is: 30
thread2 sale the ticket id is: 29
thread1 sale the ticket id is: 28
thread2 sale the ticket id is: 27
thread1 sale the ticket id is: 26
thread2 sale the ticket id is: 25
thread1 sale the ticket id is: 24
thread2 sale the ticket id is: 23
thread1 sale the ticket id is: 22
thread2 sale the ticket id is: 21
thread1 sale the ticket id is: 20
thread2 sale the ticket id is: 19
thread1 sale the ticket id is: 18
thread2 sale the ticket id is: 17
thread1 sale the ticket id is: 16
thread2 sale the ticket id is: 15
thread1 sale the ticket id is: 14
thread2 sale the ticket id is: 13
thread1 sale the ticket id is: 12
thread2 sale the ticket id is: 11
thread1 sale the ticket id is: 10
thread2 sale the ticket id is: 9
thread1 sale the ticket id is: 8
thread2 sale the ticket id is: 7
thread1 sale the ticket id is: 6
thread2 sale the ticket id is: 5
thread1 sale the ticket id is: 4
thread2 sale the ticket id is: 3
thread1 sale the ticket id is: 2
thread2 sale the ticket id is: 1
(三) 主线程中创建没有所有权的互斥量,主线程和子线程中分别等待互斥量-》主线程和子线程交替输出
(四) 主线程中创建拥有所有权的互斥量,主线程和子线程中分别等待互斥量-》只有主线程输出
这个原因不知道如何解释,难道在主线程中创建有所有权的,其他线程就永远等待不到了吗
(五) 子线程中创建拥有所有权的互斥量,主线程和子线程中分别等待互斥量-》只有子线程输出
(四)和(五)的结果可以说明在哪个线程中创建拥有所有权的互斥量,所有权永远被此线程占有,即使释放了互斥量。
以上结果都在Wince6.0测试。
后来找到一个 说明,貌似可以说明以上结论呢:
如创建进程希望立即拥有互斥体,则设为TRUE。一个互斥体同时只能由一个线程拥有。是FALSE,表示刚刚创建的这个Mutex不属于任何线程 也就是没有任何线程拥有他,一个Mutex在没有任何线程拥有他的时候,他是处于激发态的, 所以处于有信号状态。