OpenMP编程->同步机制

/* nowait用来取消栅障 */
void test12()
{
#pragma omp parallel  
	{  
#pragma omp for nowait  
		for (int i = 0; i < 100; ++i)   
		{  
			std::cout << i << "+" << std::endl;  
		}  
#pragma omp for  
		for (int j = 0; j < 100; ++j)   
		{  
			std::cout << j << "-" << std::endl;  
		}  
	}  
}

/* 显式同步栅障  在barrier处进行了同步，然后执行后边的for循环。 */
void test13()
{
#pragma omp parallel  
	{  
		for (int i = 0; i < 100; ++i)   
		{  
			cout<<"ID "<<omp_get_thread_num()<<" ";
			std::cout << i << "+" << std::endl;  
		}  

#pragma omp barrier  
		for (int j = 0; j < 100; ++j)   
		{  
			cout<<"ID "<<omp_get_thread_num()<<" ";
			std::cout << j << "-" << std::endl;  
		}  
	}  
}

/* 声明对应的并行程序块只由主线程完成  */
void test14()
{
#pragma omp parallel  
	{  
#pragma omp master  
		{  
			for (int j = 0; j < 10; ++j)   
			{  
				std::cout << j << "-" << std::endl;  
			}  
		}  

		std::cout << "This will printed twice." << std::endl;  
	}  
}

/*  section用来指定不同的线程执行不同的部分  */
void test15()
{
#pragma omp parallel sections //声明该并行区域分为若干个section,section之间的运行顺序为并行的关系  
	{  
#pragma omp section //第一个section,由某个线程单独完成  
		for (int i = 0; i < 5; ++i)   
		{  
			std::cout <<"i "<< i << "+" << std::endl;  
			cout<<"ID "<<omp_get_thread_num()<<" ";
		}  

#pragma omp section //第一个section,由某个线程单独完成  
		for (int j = 0; j < 5; ++j)   
		{  
			std::cout<<"j " << j << "-" << std::endl;  
			cout<<"ID "<<omp_get_thread_num()<<" ";
		}  
	}  
}