C++ 是否可以将 QtConcurrent::run() 与类的函数成员一起使用
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is it possible to use QtConcurrent::run() with a function member of a class
提问by yan bellavance
I can't seem to be able to associate QtConcurrent::run()with a method (function member of a class) only with a simple function. How can I do this?
我似乎无法QtConcurrent::run()仅将一个简单的函数与方法（类的函数成员）相关联。我怎样才能做到这一点？
With a regular function I cannot emit signals and its a drag. Why would anyone find this a better alternative to QThreadis beyond me and would like some input.
使用常规功能，我无法发出信号，而且很拖累。为什么有人会发现这是一个更好的替代方案，QThread这超出了我的理解，并希望得到一些意见。
回答by Kyle Lutz
Yes, this is possible (and quite easy).
是的，这是可能的（而且很容易）。
Here is an example (from the Qt documentation):
这是一个示例（来自 Qt 文档）：
// call 'QStringList QString::split(const QString &sep, SplitBehavior behavior, Qt::CaseSensitivity cs) const' in a separate thread
QString string = ...;
QFuture<QStringList> future = QtConcurrent::run(string, &QString::split, QString(", "), QString::KeepEmptyParts, Qt::CaseSensitive);
...
QStringList result = future.result();
Basically, all you have to do is pass a pointer to the object as the first argument and the address of the method as the second argument (followed by any other arguments).
基本上，您所要做的就是将指向对象的指针作为第一个参数传递，将方法的地址作为第二个参数（后跟任何其他参数）。
回答by rohanpm
The problem is that when you use a pointer to member function, you need to somehow provide the thisparameter also (i.e., the object on which the member function should be called).
问题是，当您使用指向成员函数的指针时，您还需要以某种方式提供this参数（即，应该在其上调用成员函数的对象）。
The syntax for this is quite difficult if you haven't used it before. It might be good to read http://www.parashift.com/c++-faq-lite/pointers-to-members.html.
如果您以前没有使用过它，那么它的语法非常困难。阅读http://www.parashift.com/c++-faq-lite/pointers-to-members.html可能会很好。
Say you have a class Dogand a function Dog::walkTheDog(int howlong_minutes). Then you ought to be able to use std::bind1stand std::mem_funto make it suitable for QtConcurrent::run:
假设您有一个类Dog和一个函数Dog::walkTheDog(int howlong_minutes)。那么你应该能够使用std::bind1st并std::mem_fun使其适用于QtConcurrent::run：
Dog dog;
// Walk this dog for 30 minutes
QtConcurrent::run(std::bind1st(std::mem_fun(&Dog::walkTheDog), &dog), 30);
std::bind1st(std::mem_fun(&Dog::walkTheDog), &dog)returns a function-like object which has bound the member function to a particular dog. From that point you can use it much like you could use a standalone function.
std::bind1st(std::mem_fun(&Dog::walkTheDog), &dog)返回一个类似函数的对象，该对象已将成员函数绑定到特定的狗。从那时起，您可以像使用独立函数一样使用它。
