openMP私有变量

[wuye1986]

下面这段程序

int i=0;
int a=1;
#pragma omp parallel for private(i,a)
for(i=0;i<5;i++)
{
a ++;
printf("Thread %d has a value of a = %d for i = %d\n",
omp_get_thread_num(),a,i);
}

输出结果为什么是：
Thread 0 has a value of a = 4078209 for i = 0
Thread 1 has a value of a = 1 for i = 3
Thread 0 has a value of a = 4078210 for i = 1
Thread 1 has a value of a = 2 for i = 4
Thread 0 has a value of a = 4078211 for i = 2

双核机器，在线程 0 上难道变量a就没有初始化吗？

[wuye1986]

期待。。。。

[wuye1986]

原来用private子句声明的私有变量在并行区域的入口处是未初始化的，使用之前必须赋初值，否则编译运行时会报错；即并行区域内的变量与原同名变量没有任何关系，只是名字相同而已，要继承同名变量的值，在并行区域入口处用firestprivate