C ++ 0x lambda捕获的值总是const？ [英] C++0x lambda capture by value always const?

问题描述

有没有什么方法来捕获值，并使捕获的值不恒定？我有一个图书馆函子，我想捕获&调用一个非const方法，但应该是。

Is there any way to capture by value, and make the captured value non-const? I have a library functor that I would like to capture & call a method that is non-const but should be.

以下不编译，而是使用foo :: operator（）const修复它。

The following doesn't compile but making foo::operator() const fixes it.

struct foo
{
  bool operator () ( const bool & a )
  {
    return a;
  }
};


int _tmain(int argc, _TCHAR* argv[])
{
  foo afoo;

  auto bar = [=] () -> bool
    {
      afoo(true);
    };

  return 0;
}

推荐答案

使用mutable。 >

Use mutable.

auto bar = [=] () mutable -> bool ....

如果没有可变变量，则声明lambda对象const的operator（）。

Without mutable you are declaring the operator () of the lambda object const.

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