在OpenMP线程之间进行通信(Communicating between OpenMP threads)

 我有一个OpenMP循环，我希望在任何其他线程继续之前完成第一次迭代。 我已经尝试使用全局变量，初始化为'false'，当第一次迭代结束时设置为'true'，但这似乎没有按预期工作（我陷入无限循环）。 
 
 例如： 
 
    bool FirstDone = false; // This is a global variable
    ...
    #pragma omp parallel for
    for(int i=0;i<max;i++)
    {
        while(!FirstDone && i>0){}

        if(i==0)
        {
            // Do something
            FirstDone = true;
        }
    }
 
 任何人都可以阐明为什么这不起作用？ 

I have an OpenMP loop where I want the first iteration to complete before any of the other threads continue. I've tried using a global variable, initialized to 'false', which is set to 'true' when the first iteration finishes, but this doesn't appear to work as expected (I get stuck in an infinite loop).
 
For example:
 
    bool FirstDone = false; // This is a global variable
    ...
    #pragma omp parallel for
    for(int i=0;i<max;i++)
    {
        while(!FirstDone && i>0){}

        if(i==0)
        {
            // Do something
            FirstDone = true;
        }
    }
 
Can anyone shed light on why this isn't working?

原文：https://stackoverflow.com/questions/19356500