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()<<" "; 		}   	}   }