如何从称为函数的函数中获取返回值,该函数在TBB的另一个线程中执行? [英] How to get return value from a function called which executes in another thread in TBB?
本文介绍了如何从称为函数的函数中获取返回值,该函数在TBB的另一个线程中执行?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在代码中:
#include <tbb/tbb.h>
int GetSomething()
{
int something;
// do something
return something;
}
// ...
tbb::tbb_thread(GetSomething, NULL);
// ...
此处GetSomething()
通过另一个指针在另一个线程中被调用.但是我们可以从GetSomething()
获取返回值吗?怎么样?
Here GetSomething()
was called in another thread via its pointer. But can we get return value from GetSomething()
? How?
推荐答案
如果将C ++ 03和tbb绑定在一起,则必须使用Outputarguments,这意味着必须重写函数.
If you are bound C++03 and tbb you have to use Outputarguments, which means that you have to rewrite your function.
例如:
void GetSomething(int* out_ptr);
int var = 23;
tbb::tbb:thread(GetSomething, &var); // pay attention that this doesn't run of scope
或通过boost::ref
您可以执行以下操作:
or with boost::ref
you can do this:
void GetSomething(int& out);
int var = 23;
tbb::tbb_thread(GetSomething, boost::ref(var)); // pay attention here, too
如果可以使用C ++ 11,则可以使用futures
简化任务:
If you can use C++11 the task is simplified by using futures
:
例如:
std::future<int> fut = std::async(std::launch::async, GetSomething);
....
// later
int result = fut.get();
这里您不必重写任何内容.
Here you don't have to rewrite anything.
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