[置顶]       OpenMP编程->互斥锁函数

//互斥锁同步   #pragma opm atomic   x< + or * or - or * or  / or & or | or << or >> >=expr void test9() { 	int sum = 0;     	std::cout << "Before: " << sum << std::endl;   omp_set_num_threads(3);  #pragma omp parallel for   	for (int i = 0; i < 20000; ++i)    	{   #pragma omp atomic   		sum++; 		//cout<<"ID "<<omp_get_thread_num()<<endl; 	}    	std::cout << "After: " << sum << std::endl;   }

//临界区声明方法,可以对某个并行程序块进行防护。 void test10() { 	int sum = 0;     	std::cout << "Before: " << sum << std::endl;    #pragma omp parallel for   	for (int i = 0; i < 100; ++i)    	{   #pragma omp critical (a)   		{   			test9(); 			sum = sum + i * 2;   		}   	}    	std::cout << "After: " << sum << std::endl;  }

/*  对for循环中的所有内容进行加锁保护，同时只能有一个线程执行for循环中的内容。  */ static omp_lock_t lock;  void test11() { 	omp_init_lock(&lock); // 初始化互斥锁    #pragma omp parallel for   	for (int i = 0; i < 5; ++i)    	{   		omp_set_lock(&lock); //获得互斥器    		std::cout << omp_get_thread_num() << "+" << std::endl;   		std::cout << omp_get_thread_num() << "-" << std::endl;   		omp_unset_lock(&lock); //释放互斥器   	}    	omp_destroy_lock(&lock); //销毁互斥器   }